Bad Hard Drive Signs and Symptoms - A Guide for Mac Users
Hard drives store most, if not all the data on your system, and when they go down, the results may be disastrous. Many people take the hard drive for granted because they're generally extremely reliable. When problems finally occur,  a user may find themselves in dire straights because critical and personal information, such as financial data, years of tax returns, and personal items such as photographs, music, and documents may suddenly be gone forever, especially if no backups have been made.  It's important to know the signs and symptoms of a possible drive problem because if one is developing, the user will hopefully be able to take the steps needed to minimize potential disaster.
This article is not a formal and in depth treatise on hard drive problems but rather an article intended to help people determine whether or not the problems they may be having might be traced to a hard drive. This article focuses only on mechanical hard drives, not solid state drives (SSDs.)
Here at SCSC, we offer a line of products known as Scannerz, which is for Macintosh systems running MacOS X. When we start getting into the actual process of identifying problems, we will of course be referencing our products in some of the examples, but most of the information is not tied to our products, or for that matter even Macintosh computers. For those interested in more information about our products, brief descriptions and links to more product information may be found at the end of the document.
People interested in much, much more detail regarding hard drive and system related problems should check out our downloads section by clicking HERE. The document you might be interested in will likely be the following:
Hard Drive Troubleshooting
This document is quite technical and lengthy, and is likely beyond the scope of most users. All the downloads are free and in PDF format, so feel free to download any that you think might be of interest to you.
Finally, for Mac users, if you review this document and you’re having some type of system/performance problems and you’re reasonably sure the drive can be eliminated as the source, you might want to check out another article in our site’s how-to section titled Evaluating Mountain Lion Performance Problems with Activity Monitor by clicking HERE. Although the document is targeting Mountain Lion (MacOS 10.8) the procedures are generally applicable to earlier releases of Mac OS X as well, and although the user interface for Activity Monitor in Mavericks (MacOS 10.9) has changed, it may still be of value because procedurally it's nearly identical.
How Long Does a Hard Drive Last?
A hard drive, like anything else, may fail at any moment for a wide variety of reasons. However, most data on hard drive reliability indicates that a very small percentage of drives will fail very quickly after being put into service, while the vast majority will last a fairly long time (several years) before encountering problems. After a certain period of time, which is drive specific, the failure rates typically rise and rise rapidly.
Hard drives do not last forever, even if they're not used. As time progresses, the media on the platter deteriorates and the drive will fail to retain information. It's a mistake to assume that data may be put on a hard drive and then locked away in a safe place to be recovered years later. All data may be lost. How long a drive is able to retain data is related to the magnetic coating on the drive, the storage temperature and humidity, and the cleanliness of the storage environment.
For example, here at SCSC, since drive testing is one of the key functions of our Scannerz product line, we subjected a drive manufactured in 2002 to tests during the development of our Scannerz products in 2009. At that time, the drive was in fine working order. Our tests indicated no bad or weak sectors and no problems with the seek mechanism. The drive was then put into storage and left alone. Recently, we pulled the drive and subjected it to more tests. The operating system complains about the drive when activating it, and surface scan tests on the drive with Scannerz almost immediately produce weak sectors followed by bad sectors, and the damage is not isolated to one section of the drive. In this case, the media itself is failing. We included some videos of this drive being tested below in the "Periodic Lockups and Delays Section" as the second and third videos, for those interested.
Laptop drives will almost invariably have shorter lifespans than their desktop counterparts because they're typically subjected to more abuse, such as being moved around or even dropped or bumped while the reading/writing operation is in progress. Head crashes, which can often be corrected by reformatting and zeroing the drive, are much more common.
Other factors that can cause early drive failure include use, meaning how often the drive is reading and writing data, temperature, and environment. A drive that's used to host a database or web server is usually constantly reading and writing data and will be more prone to mechanical failures. A drive that's constantly used in a hot environment will wear out more quickly. A drive used in an environment that may introduce micro-particles into the drive chamber (which isn't sealed) will likely suffer from more head crashes than other drives. This is usually an industrial environment.
An Overview of a Hard Drive
The figure below illustrates the major components of a hard drive. We're not going to focus too much on the theory of operation of a hard drive because there are already plenty of documents available on the web that can do that. Instead, we'll go lightly over how a hard drive works and then focus specifically on failures, and how they manifest themselves to the end user.
When a drive needs to read or write data to a drive, the CPU on the logic board sends a set of commands to the drive through what's called an I/O controller. The I/O controller, which is on the logic board, is usually connected to the drive via an interface cable. The commands the I/O controller uses are fairly high level, such as "get me this number of blocks of data between points A and B on the drive" or "write the following blocks of data to the drive between points C and D." This is obviously an over simplification. Once the I/O controller delivers the commands, it's the duty of the drive controller to implement them and return the appropriate response codes, and in the case of read operations, data back to the system.
Data is written to and read from the drive platters via the drive's heads, which are positioned via an actuator arm. The actuator arm behaves in a manner similar to the tone arm on a record player, but it's constantly moving around on the platter at very high speeds. The drive platters are coated with a magnetically modifiable material that can be used to store information based on the localized magnetic state of a region of the platter. The information on the platters is broken down into what are called cylinders and sectors, along with tracking and positioning information. The tracking information is read by the drive heads and interpreted by the drive controller to position the drive heads to the regions of the platter that will eventually be used to read or write data on the platter.
During a write operation, after the controller positions the drive's heads over the appropriate region of the drive, they modify the surface of the platter by inducing an electromagnetic field over the magnetically modifiable platter surface. During a read operation, the spinning nature of the platter is able to induce a current into the heads much in the same way that a moving magnet can induce a current into a wire. The storage unit on the platter is the sector, which typically stores 512 bytes of information, although newer drives may have sector sizes of 4 kilobytes.
The drive controller, which isn't seen in the diagram is, for those that have seen  a contemporary hard drive, the circuit card that usually takes up the better part of the bottom of the drive. The drive controller is responsible for positioning the drive heads over the drive's platters (the media used for reading and writing data,) activating the drive's heads for reading and writing data when the heads are properly positioned, interpreting and converting the data to a format the CPU can understand, and then sending the appropriate codes to back to the CPU via the I/O controller. During a write operation, the controller will send the system codes indicating whether or not the write operation succeeded. During a read operation, the controller will send the system blocks of data accompanied by response codes indicating the operation succeeded or failed.
The platter is connected to a spindle, which in turn is connected to the spindle motor. The spindle motor is not seen in diagram, but it's underneath the platter(s) and spindle. The spindle motor keeps the platter(s) rotating at a constant velocity, with todays drives typically using speeds between 5400 and 7200 RPM, with some higher performance drives using speeds as high as 15000 RPM. The actuator arm rotates about an actuator axis, with one end having wound coils embedded between a set of actuator magnets, and known as the actuator. The position of the actuator is controlled by increasing or reducing  the current passing through these coils, which cause the actuator to move. All of these functions are controlled/regulated by the drive controller.
Types of Drive Failures and Problems
Drive failures can generally be categorized into the following classes:
    •    Electromechanical
    •    Mechanical failures
    •    Head/platter failures
    •    Controller failures
    •    Drive related problems
Electromechanical failures typically affect the spindle motor or the actuator. Spindle motors, like any motor can simply burn out. The actuator is typically connected to the controller via a flex cable that can develop cracks, break, or become disconnected. Actuator windings can conceivably fail as well. Either of these failures are catastrophic failures, and the drive will not be accessible by the system.
Both the actuator assembly and access to the spindle motor typically required disassembly of the chamber containing the drive platters themselves. If data recovery is needed, the drive will need to be sent to a facility specializing in this procedure.  The procedure typically consists of putting the drive in a clean room, disassembling the drive housing, extracting the platters, and then putting them on a donor device to recover the data. Failures of this nature often leave the platters unaffected and the odds that data recovery will be successful are reasonably good, but this procedure is typically expensive. Failures of this nature are usually due to age, and the older and more used a drive is, the higher the probability of their occurrence is.
Mechanical failures are typically, once again, related to the spindle motor and the actuator. In this case the typical cause of failure is bearing wear. The drive's heads typically "float" over the surface of the platter by only a few nanometers, and as the bearings in one or both components wear, it causes excessive motion of the heads over the platters, eventually resulting in head crashes with increasing frequency. The head crashes damage the sectors of the drive containing data, and as time progresses, the problem gets worse and worse.  
If mechanical failures start to occur, you should make sure that you're backing up data frequently, and you shouldn't be surprised if some files fail to backup because they're unreadable. If you use a test tool such as Scannerz, the tell tale sign of this problem will be the development of confirmed bad or weak sectors (damaged, but still readable) on the drive with increasing frequency. Seek scan errors and irregularities may also not only occur, but start becoming rampant. In extreme cases, a head crash caused by this problem may spew platter material over other regions of the platter, causing other head crashes. The older a unit is, and the more use it receives, the higher the probability is that this problem will occur. Any regions of the platter damaged will either be unrecoverable or only partially recoverable.
Head and platter failures can occur on any drive, new or old. They're typically referred to as a "head crash." In the preceding two paragraphs we described how they can be induced by mechanical failure, but they may also be induced when the drive is subjected to excessive shock or when a contaminant enters the chamber of the drive. Head/platter failures are characterized by the presence of bad or weak sectors, but in the case of impact or contamination, these may be one time events. In some cases, they may be caused by actual defects in the platters surface. A bad sector is a sector that is so damaged it can't have its data read and will generate an I/O error. A weak sector is a sector that can still have it's data recovered, but only after a number of read attempts.
In the case of shock or sudden impact, the drive is typically in the process of reading or writing to the drive when the event occurs. This problem is obviously more common with laptop computers that might be dropped while in use. The impact causes the heads to be forced onto the platter, damaging the media. The result is typically a range of bad or weak sectors localized to a region of the drive. Many contemporary systems and drives have sensors installed on them to move the heads off the platters in the event of impact, but they aren't 100% reliable - they cannot perform miracles!
In the case of contamination, a particle of some sort has "leaked" into the drive chamber. Hard drives are not working in a vacuum environment, they rely on the presence of air in the drive chamber to "float" the drive's heads over the platter. To equalize the air pressure, drives have a small breather hole with a filter on the exterior of the drive. If a particle can make its way past this filter, the particle may come between the platter and the heads, thus damaging sectors. The damaged sectors may be bad or weak sectors, or a combination of both.
Crashes due to impact are more common in laptops, particularly if the computer is dropped while in use. Crashes due to a contaminant entering the chamber can occur on any hard drive at any time, but they're not common. In most cases, these are one time events, but if the crash is bad enough, it may spew other damaged platter materials over the surface of the platter causing other sections of the platter to be damaged. In severe cases, the heads themselves may be damaged in which case the drive is typically rendered useless.
Bad or weak sectors caused by media should, theoretically, be detected and corrected by the drive manufacturer prior to releasing the product for sale. However, some sectors can tend to lose their ability to retain information over time. This is usually a localized problem and can often be corrected by formatting the drive to re-map the bad sectors to spare sectors. As a drive ages, it may begin to lose its ability to store information all together. Do not assume you can put critical data on a drive, store it for 15 years, and expect it to be readable.
It is not uncommon for a hard drive to develop some bad sectors. In many cases, this problem can be corrected, but with hard drive prices being as low as they are, in our opinion it's not an unreasonable to consider replacing the drive. As stated earlier in the chapters regarding mechanical failure, if the bad or weak sectors are being caused by such a problem, the number of bad or weak sectors will only continue to increase. Efforts to salvage a drive are often time consuming, and if the problem is actually being caused by a developing mechanical failure, the repair process will need to be repeated over and over again. We recommend that the users of our Scannerz line of products that opt to repair a drive increase testing initially to confirm that the problems are not increasing with use.
Controller failures can range from the obvious to the insidious. An obvious controller failure could be caused by a failure of the supply regulators on the drive controller preventing the controller from actually  powering up. If components on the controller fail, in most cases the controller will prevent the drive from being seen by the system. If a drive is having intermittent problems of some sort, the drive activity is typically very erratic and unpredictable. Last but not least, the controller, being essentially a small computer system itself has its own firmware which can, unfortunately have some bugs in it, and drives suffering from this problem are often recalled by the manufacturer. Controllers do fail, but the reality is it's the most reliable part of the hard drive and the least likely to fail. Most controller failures make the drive completely invisible to the system.
Drive related problems may occur when a  hard drive may appear to be suffering from a problem, when in fact it's being caused by another component. The most common problem is usually a bad cable or connection in the data cable or power cable between the system and the drive. Another, more obscure, and often difficult to isolate problem can occur when cracks develop in the logic board or connectors on the logic board that lead to the drive. All of these problems are typically erratic and difficult to repeat, and they usually get worse as time progresses. Logic board components themselves may be failing erratically, but in this case the result is most often that the system will fail to boot or crash repeatedly without warning.
Symptoms of Hard Drive and Drive Related Problems
The typical signs of a drive or drive related problem are usually the following:
    1.    The drive is making excessive noise
    2.    The drive isn't recognized by the system at all
    3.    The system appears to periodically lock up or delay, often accompanied with a "spinning beach ball."
Item 1. above, if confirmed, is truly a drive problem, and it typically indicates that the drive is failing and needs to be replaced. Items 2. and 3. however, may not be drive related, but caused by other problems in the system or even the software.
Hard Drive Noises
Abnormal hard drive noises typically consist of the following:
    •    Clicking noises
    •    Grinding noises
    •    Squealing noises
    •    Noises similar to a vibration noise
Optical drives may make some of these noises as well, and it's relatively easy to confirm this because noises from an optical drive will only occur when the optical drive is in use or being activated or checked by the system. For the rest of this article, we'll assume that the optical drive has been eliminated as the source of noises.
Clicking noises may or may not be a problem. If the drive has head problems, a repetitive clicking can be caused by controller detecting a failed operation and repeating it over and over again. These will be fairly loud, repetitive clicks. If the drive controller has failed or the firmware has a bug in it, a repetitive clicking sound may be generated by the drive heads slamming into an actuator arm stop (or even the spindle.) These too, will be fairly noticeable and repetitive. Other drives are just plain noisier than others by design and may be characterized by rapid, mild clicking or rattling sounds as the actuator arm moves over the surface of the platters during read and write operations. This is more common in older drives. The general rule of thumb is to be aware of clicking noises that are new, as opposed to noises that existed from day one. New, loud clicking noises, particularly if they're repetitive usually indicate the drive is failing if it hasn't already failed.
Grinding noises can be repetitive, random, or continuous. One type of grinding noise, although we're not sure it should really be called a grinding noise, is a periodic and repetitive "chug-a-chug-a-chug-a" noise, often accompanied by "spinning beach balls." This is typically being caused by the drive attempting to access a bad or weak sector. A bad sector will generate an I/O error, but a weak sector can be read, it just takes a long time (often seconds) to read it. If you're using Scannerz for drive testing, a bad sector will be a sector that fails with an error every time it's scanned, and a weak sector will be identified as a repeatable irregularity. Other grinding noises are usually caused by mechanic failure in the process of developing. Bad and weak sectors can, in some cases be corrected, but mechanical failures indicate that the drive is in the process of failing, and steps should be taken to backup the drive while it's still usable.
Squealing noises coming from the drive can be caused by several sources, with none of them being good. The noises may be erratic or consistent. Consistent squealing usually indicates that the spindle motor that drives the platters is failing. Erratic squealing may also be the bearings in the spindle motor failing, but they may also be sourced to the bearings in the actuator, or possibly even the heads of the drive dragging across the surface of the platter. These are all serious, catastrophic failures in the process of occurring. You should attempt to backup the drive as soon as possible…if it's even possible.
Noises similar to a vibration noise typically occur when an item in the drive is in the process of seizing. The noise is usually due to binding of either the spindle motor bearings or the actuator bearings (more common.) In some cases, the electromagnetic energy being supplied to either of these components may eventually allow the component to free itself and the vibration ends in an almost erratic manner, only to occur again. These are signs that the drive is failing and needs to be replaced. Data should be backed up and the drive replaced as soon as possible. However, as you'll see in the next few paragraphs, you will need to make sure the noises need to be properly traced - a set of bad drive mounts or perhaps a drive that isn't properly tightened or installed can end up presenting the user with similar sounds.
If a drive is suspected of making noise about the only thing you can do is confirm the source of the noise is the drive, and if confirmed, retrieve as much data as possible and replace the drive. There aren't very many moving components in a computer system, but the source needs to be identified. Other sources of noises in a system that can often sound like hard drive problems consist of the following:
    •    Vibration in other parts of the unit
    •    Noisy cooling fans
    •    Optical drives
    •    Other drives
Of the list above, vibration of loose components can be the trickiest to isolate because vibrating components, especially shielding, may correlate with drive activity because the drive's vibration is inducing the noise into the component making the noise. Unfortunately, some modes of drive failure also sound almost exactly like noise associated with vibration. In some cases the unit may need to be opened up and the actual source of the noise traced to its source.
Cooling fans have bearings, and when their bearings begin to fail, the noise can be similar to some of the squealing noises a failing drive can produce. The difference between the two is typically that, at least in most systems, the speed of the fans varies and at some times the fans may not be running at all. Another problem occurs when another component, such as a wire or a piece of shielding is making contact with the fan blades. This can induce a vibration-like noise that may be mistaken for a failing drive. One way to determine if the noises correlate to fan operation is to put your hand over the vents of the system and see if the noise corresponds to air movement being generated by the fans when the system is running a little on the hot side.
Optical drives can often produce noises that can be similar to the sounds generated by a failing drive. In laptops, optical drives are known to cause vibration noises as their mounts come loose or they come into contact with shielding material. Optical drives when initializing or loading optical media may often make clicking noises. Optical drives can fail, often going through cycles of resetting and repositioning the heads producing a repetitive clicking noise similar to that of a failing hard drive.
Finally, if a system has multiple hard drives in it, and it's believed the noises are being generated by a hard drive, the owner will need to determine which drive is making the noise. One way that might help identify the problem is to unmount the secondary drives one by one using Disk Utility to see if the noises stop. This may work, especially if the unmounted drive stops spinning, but in some cases the drive may continue spinning and further evaluation will be needed.
The Drive Isn't Recognized by the System
If the hard drive isn't recognized by the system, it may or may not be a drive failure. The following items identify what can cause the drive to be unseen:
    1.    The drive's controller has failed
    2.    The drive's power source has become disconnected
    3.    The drive's data cable has become disconnected
    4.    The drive isn't formatted or it's in a format the operating system doesn't recognize
    5.    System Management Controller (SMC), NVRAM, or PRAM need to be reset
    6.    The drive's indices are corrupt
    7.    A logic board problem exists
The drive not being recognized by the system may happen to both primary (bootable) and secondary drives. On a primary drive, the system will fail to boot and when the system is powered on, the user will be confronted with one of the following symbols:
A bad sector is a sector that cannot be read, whereas a weak sector is a sector that can be read, but only after the drive controller attempts to read it many times. A bad sector is damaged to such an extent that the controller can't make any sense of the data and after making many attempts to read it, it gives up and the system issues an I/O error. A weak sector is one that may be be physically damaged or be caused by a defect in the drive platter surface. When a weak sector is encountered, the controller reads and re-reads it until it's algorithms can confirm that the data has been recovered. Unfortunately this process can take seconds (a typical sector is read in milliseconds.) Both of these problems will cause delays and what appear to be system lock ups often accompanied by the notorious "spinning beach balls." A bad sector may cause a system to appear to lock up for over a minute, and a weak sector, depending on how weak it is, may induce waits ranging from a few seconds to tens of seconds. If the system needs to read a bad or weak sector numerous times, the system will appear to be locking up or delaying frequently.
Another cause of lock ups or delays is cracked logic board traces, bad solder board connections, intermittent contact in faulty cables, or actual logic board components in the process of failing. Internal SATA cables on some laptop computers seem to be particularly susceptible to failure - more so than their desktop based counterparts. These types of problems are initially intermittent and erratic in nature and they typically get worse and worse as time progresses. The problems are often related to system heating because heat will cause the faulty components to expand and contract as the system heats and cools. When hot, thermal expansion causes the cracks to separate, and electrical flow is interrupted. When they cool down, the cracks decompress, resume contact, and electrical flow resumes. When the system attempts to send data to the drive during a period of disconnection, it will keep trying, over and over again until it registers an I/O failure (if the period of disconnection is long enough) or succeeds, which in some cases may take seconds. The result to the end user of the system appears to be functionally identical to that of bad/weak sectors, namely delays and lockups.
The way to tell if the problems are being caused by bad/weak sectors or by intermittent connections caused by faulty logic board traces, solder joints, or bad cables, is very simply isolated using Scannerz. Bad or weak sectors will always be repeatable, whereas those associated with intermittent contact will not be repeatable. Scannerz Diagnostics Mode can evaluate these problems by confirming whether or not the problems are consistent. If inconsistency exists, the problems will typically be exposed using the Diagnostics Mode interface testing option.The vast majority of intermittent connection problems will be traced to drive cables.
Some applications may cause excessive delays that can emulate hard drive problems. The most notorious of these is Spotlight indexing, which can be both CPU and drive intensive. We've published a how-to article on evaluating system performance problems using Activity Monitor with a focus on Spotlight indexing which may be viewed by clicking HERE. However, Spotlight indexing may not be the source of the problems. Depending on the user's environment, there may be other applications running in the background that are drive or system intensive that the user is unaware of. This is why all versions of the fully featured releases of Scannerz comes with FSE or FSE-Lite. These are file system events monitors that can help expose applications running in the background that are drive intensive but hidden from the end user.
Software Problems
Technically, software problems aren’t typically drive problems, but in some cases they may make the system experience lockups and delays similar to those described in the preceding section. Generally speaking, software problems can be often be traced to the following:
    •    Spotlight and Time Machine MDS indexing
    •    Anti-virus software
    •    Driver problems or conflicts
    •    Intensive background processes the user is unaware of
    •    The user has installed "cleaning" programs
Spotlight and Time Machine indexing, particularly in Leopard, Mountain Lion, and Mavericks can be particularly problematic. Indexing is performed by a process called the meta data server (MDS.) During an indexing session, MDS will index every file on attached drives as defined in Spotlight’s Search Results and Privacy settings in System Preferences, as well as every Time Machine volume. Indexing is drive, CPU, and often memory intensive. When indexing occurs it’s not uncommon for some applications that normally “pop up” when launched to take many seconds to launch, along with “spinning beach balls.”
One way to check this is to click on the Spotlight icon in the upper right section of the menu bar and check if it’s in the process of indexing or beginning an indexing session, but that will only show you indexing associated with Spotlight, not Time Machine. You can also monitor MDS activity by downloading our free tool, named Spot-O-Meter by visiting our SpotOff page by clicking HERE. Spot-O-Meter is free, SpotOff isn't. Spot-O-Meter will show the level of all MDS activity, not just that associated with Spotlight.
Some anti-virus software will cause problems similar to drive problems because they misidentify valid applications or processes as viruses and block them from running, thus causing lockups and delays. The easiest way to check this is to disable the anti-virus software, see if the problem clears up, and if it does, contact the vendor for assistance.
Driver problems or conflicts can sometimes occur, particularly with add on devices such as external hard drives after an operating system is updated or upgraded. Problems can range from extremely slow performance to what appear to be drive failures. If problems that didn’t exist prior to an operating system update or upgrade, you should contact the vendor and ask if there are any known conflicts they’re aware of. If possible, you might want to try to remove any drivers.
Some applications may install CPU or drive intensive processes that work in the background without your knowledge. When it became apparent to us that some people were purchasing our earlier versions of Scannerz to test what they thought were problematic drives only to find out the drive wasn't the problem, we expanded some of the tools included with Scannerz to include FSE/FSE-Lite and Performance Probe to help out. If these tools are used in conjunction with Activity Monitor, these may help a user identify the cause of their problems.
FSE and FSE-Lite are file system event monitors that can indicate excessive file system activity, with FSE being able to be configured to target specific applications, users, or file/folder activity. Performance Probe was designed to be a "shorthand" version of Activity Monitor that summarizes system loading allowing users to bring up the full version of Activity Monitor to evaluate problems when excessive loading occurs. Both tools may be purchased as stand alone applications, but before considering purchasing an FSE license, please read the product profile for it and the information on the section of our site dedicated to FSE because it is generally not a tool for novices. All versions of the fully featured version of Scannerz come with a version of FSE or FSE-Lite, along with Phoenix (a drive cloning and operating system extraction tool,) and Performance Probe.
There are several "cleaning" tools being offered on the market. Before downloading any such applications we strongly recommend checking them out on other web sites, or find someone that's used them before and see what they're experiences are. If such an application deletes critical system files mistakenly, it can cause not only possible performance problems, but in some cases it may prevent the system from booting properly.
Our Product Line Up
Scannerz with FSE or FSE-Lite are our original, fully featured drive and system testing products and now come with Phoenix and Performance Probe (described below) as well. These packages are intended to be used by people that not only want to test their drive and system, but be able to isolate the cause of the problems as well. These versions of Scannerz can help a user detect and isolate drive or SSD problems, problems with bad cables, and system bus or memory problems. It's new Diagnostics Mode can be extremely useful, especially when evaluating erratic problems that may be difficult, if not impossible to test with other applications.
Scannerz Lite is a very low cost, much simpler version of Scannerz that can be used by anyone, literally anyone, to test their primary and backup drives to determine whether or not they're working OK. Scannerz Lite will test your drives and simply gives a pass/fail indication at the end of a test, with a "fail" status indicating that you need to take your unit in for servicing. The user interface of the application and log files can indicate the severity of damage on a bad drive.
FSE and FSE-Lite are file system event monitors. Heavy file system activity can often delude a user into believing there's something wrong with their drive or system, when in fact it's often a background process accessing the drive with such intensity it appears to be locking up. FSE-Lite is included in the base system of Scannerz at no cost, or the user may opt to upgrade to the fully featured version of FSE. The fully featured version of FSE may be purchased as a standalone product and is configurable, allowing it to be used to target specific file system events. FSE is generally not a tool for novices and anyone interested in it should visit the FSE page on this site and read the product profile before ordering it. Price: $19.95
SpotOff with Spot-O-Meter is an mds indexing controller. The mds process (meta data server) is used by both Spotlight and Time Machine to index systems, sometimes at very inconvenient times. The end result is often considerable system slow downs, excessive battery drain, and in laptops, heating. SpotOff allows the user to control mds indexing, and Spot-O-Meter allows a user to monitor its intensity at a given instant.
Phoenix is a basic drive cloning and operating system extraction tool. Phoenix allows the user to extract the core OS from their own boot volume and create an emergency boot volume that can be used to host testing tools, such as Scannerz, or restore the core OS onto another volume. It also performs basic volume cloning. Phoenix is included in Scannerz with FSE or FSE-Lite.
Performance Probe is a system load monitor that may be used to help identify system bottlenecks caused by memory, I/O, or CPU intensive applications. Performance Probe illustrates memory usage in a manner similar to that of older versions of OS X that preceded Mavericks. This application is also included in Scannerz with FSE or FSE-Lite.
   Click HERE to visit the product page for Scannerz and Scannerz Lite.
   Click HERE to obtain more information about SpotOff with Spot-O-Meter
   Click HERE to obtain more information about the standalone version of Phoenix.
   Click HERE to obtain more information about the standalone version of Performance Probe.
Brought to you by Scannerz with Phoenix and FSE for the Mac OS X Operating System. If you have hard drive problems or want to evaluate your drive or system, click on the icon to the left for more information. If you would like to create your own operating system diagnostic drive or clone an existing volume to another drive without Scannerz, check out the standalone version of Phoenix for Mac OS X by clicking on the Phoenix icon to the right. Phoenix is included in the full versions of Scannerz.
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On a secondary drive, the drive will not be shown as being available on the system.
In the event the drive controller has failed, unless you're interested in replacing the drive's controller card yourself, the drive should be considered dead. Replacing a drive controller isn't that difficult a job to do for someone with any experience working on computers, however it's critical that the controller replacement have the exact same type of card and ROM. Manufacturers frequently update these, and a mismatch can end up being disastrous. In many cases, however, the data on the drive can be recovered. A failed controller will yield a drive that does not show up at all in the system or when using Disk Utility.
Power sources and data cables can become disconnected or develop complete  breaks in the wires inside the cables. This most commonly happens in external drives. External drives are easily serviced because cables or supplies suspected of being bad can be easily swapped out, but if the problem is with internal drives, then the unit will need to be opened up. You may still find that the problem is elsewhere, for example the supply on the external drive may have failed, or perhaps the controller card on the drive inside the system or inside an external enclosure may have failed as well.
If the drive isn't formatted properly or its index files have become corrupt, the unit may not show up as a viable unit, but it will likely show up using Disk Utility. Normally a drive will show up in Disk Utility with its volume name, but if it shows up with an actual drive designation (such as disk0s2, for example) then this might be a hint as to what's happened with the drive.
The System Management Controller, NVRAM, and PRAM all store parameters that the system can use to store system settings including boot information. These can become corrupt, and if they do, a reset may make a once invisible drive visible again. The following two links identify how to reset these parameters:
Finally, logic board problems may exist that will render booting useless using an affected port. One way you might be able to check this is to try booting from another drive. For example, if an internal drive has failed, attempt booting from an external drive or using the system's install disk (if equipped with an optical drive). If all attempts to boot using auxiliary devices fail it's likely there's a problem with the I/O controller. If you can boot from an auxiliary drive, then the problem is likely not the logic board but possibly bad cable or supply connections feeding the drive. If the source of the problem is the logic board itself, the drive may very well be in good working order with all data retained.
Periodic Lock Ups or Delays
Periodic lock ups or delays, often accompanied by "spinning beach balls" are probably the most common form of a drive problem. When we say this is a "common form of failure" we don't mean this happens frequently, we mean that of the problems that occur with a drive, this is probably one of the, if not the most common. It is not uncommon for a contemporary hard drive to last years without having any problems at all.
Delays and lock ups are usually caused by bad or weak sectors on a drive, but they can also be caused by cracks in logic board traces and solder joints or intermittent connections in cables. Bad or weak sectors, if using test software such as Scannerz, will always be repeatable - the bad sectors and weak sectors will show up at the exact same places every time a scan is done on the drive. If the problem is caused by intermittent connections in the logic board or bad cables, the problems will show up erratically during a hard drive scan and can't be correlated to the progress of the scan on the drive. In some cases, software running on the system may be the culprit, with the most notorious culprit being Spotlight indexing of a drive.
The following three short videos illustrate delays caused by weak and bad sectors. The first video illustrates a hard drive in good condition being tested in Normal Mode by Scannerz. This video is provided to visualize how smoothly a drive in good working order functions. The second video illustrates a failing hard drive during a Scannerz Normal Mode test. The third video is a Diagnostics Mode scan on the failing drive using Scannerz, which reevaluates the detected irregularities and errors and confirms them as weak and bad sectors.
Bad cables and faulty connectors can have the exact same types of performance effects on a system from a user perspective as do weak and bad sectors.  Bad and weak sectors will generally be repeatable with respect to the location on the drive, whereas problems caused by failing cables, connectors, etc. will occur at random with respect to the location on the drive. This is why re-evaluating and confirming problems is critical.
In the first video, we have a drive in good condition being tested by Scannerz in Normal Mode. Notice that the text on the user interface indicating the test ranges is progressing smoothly and without interruption. This is only a brief portion of the scan. Notice that the error and irregularity counts are both zero. The video clip starts when the scan was in the 0.026GB to 0.027GB range of the drive and the clip was terminated when the scan range entered the 1.253GB to 1.254GB range.
In the second video, Scannerz is evaluating a bad hard drive. Notice that even though initially no problems are detected, the progress is not uniform. When Scannerz enters the 0.375GB to 0.376GB scan range, the scan slows down, and "spinners" come up. Observe the presence of two irregularities followed by an error in this range. Once past the bad sector, probing is performed for a while and normal scanning resumes. Finally the video ends when the user terminates the test.
In the third and final video, Scannerz is put into Diagnostics Mode to evaluate the problems encountered in the preceding video. With the logging window already open, tests are configured to evaluate errors and irregularities from the preceding test. The two irregularities are confirmed as weak sectors, and then finally the error is confirmed as a bad block. The logging window indicates how much time it took to successfully access the weak sectors. Typically, a sector should be read in terms of milliseconds, not seconds! As the logging window indicates, the data in the bad block cannot be recovered.