Disk Diag Mac
If you think your Mac might have a hardware issue, you can use Apple Diagnostics to help determine which hardware component might be at fault. Apple Diagnostics also suggests solutions and helps you contact Apple Support for assistance.
Prepare your Mac
- Shut down your Mac.
- Disconnect all external devices except keyboard, mouse, display, Ethernet connection (if applicable), and connection to AC power.
- Make sure that your Mac is on a hard, flat, stable surface with good ventilation.
Start Apple Diagnostics
Disk Drill (Free / $89) - Disk Drill provides Mac users with data recovery capabilities. If you’ve deleted a file, wiped a drive or any other type of data loss that isn’t the result of a failed hard drive, Disk Drill makes every attempt to recover it. It’s available as a free app for scanning for lost files and folders. Jan 18, 2012 While Disk Utility doesn't fix physically failing disks, it can help speed diagnosis. Using Mac OS X Lion, open Disk Utility (found in Applications Utilities). Select the Mac's system disk.
Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:
Apple silicon
- Turn on your Mac and continue to press and hold the power button as your Mac starts up.
- Release when you see the startup options window, which includes a gear icon labeled Options.
- Press Command (⌘)-D on your keyboard.
Intel processor
- Turn on your Mac, then immediately press and hold the D key on your keyboard as your Mac starts up.
- Release when you see a progress bar or you're asked to choose a language.
View the test results
Apple Diagnostics shows a progress bar while it's checking your Mac:
When testing is complete, Apple Diagnostics shows the results, including one or more reference codes. Learn about Apple Diagnostics reference codes.
To repeat the test, click “Run the test again” or press Command-R.
To restart your Mac, click Restart or press R.
To shut down, click Shut Down or press S.
To get information about your service and support options, make sure that your Mac is connected to the internet, then click ”Get started” or press Command-G. Your Mac will restart to a webpage with more information. When you're done, choose Restart or Shut Down from the Apple menu.
Learn more

On an Intel-based Mac, if you can't start Apple Diagnostics with the D key, try these solutions:
- Press and hold Option-D at startup to use Apple Diagnostics over the internet.
- Make sure that your Mac isn't using a firmware password.
DriveDx will protect you from data loss and downtime
With DriveDx you need not worry about losing your important data, music, and photographs.
You can know before your drive is going to fail, because DriveDx tracks more indicators of impending failure than any other product on the market for both SSDs and HDDs.
Early Warning System
You will have more chances to save your critical data before any data loss actually occurs.
Modern SSDs and HDDs support

When evaluating the state of various drives, DriveDx can use different heuristic algorithms depending on the drive model and even its firmware version.
Drive Self-tests
Disk Diag Mac Download
Will help to quickly identify if the drive is faulty.
Automatic Email Reports
User does not need to have physical access to a specific computer all the time, which is especially useful for all kinds of server rooms, data centers, etc.
This is one of the best investments you can make in your system. I recommend it highly.
DriveDx app warned of pending drive failure before it happened. Nice!!! @binaryfruit
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Advanced Drive Health Diagnostics
Regular diagnostic tools simply check the built-in S.M.A.R.T. status of the drive, which provides the user with little information about the actual state of the physical drive. As opposed to such tools, DriveDx analyzes the current state of the drive using all the drive health indicators that are most likely to point to a potential drive issue (for instance, SSD wear out / write endurance, I/O errors, pending sectors, reallocated bad sectors, etc). See competitive analysis against several popular products hereDrive Failing (Pre-fail) State Detection
Unlike most other tools, DriveDx detects not only “OK/Verified” and “Failed” drive health states, but also the “Failing (Pre-fail)” drive state. Thanks to that, you will detect problems much earlier than when using any other SMART monitoring utilities. This means that you have more chances to save your critical data before any data loss actually occurs. Learn moreMac Disk Utility

Real-time Drive Health Monitoring
DriveDx runs in the background and periodically performs checks to determine the health of your SSD or HDD. When any issue or problem is found, it alerts you immediately. DriveDx acts as an “early warning system” for pending drive problems. As a result, you have more chances to save your critical data before any data loss actually occurs.Early Warning System
DriveDx features a special multi-tier warning system that will inform the user about deviations from the normal state of drive attributes. It constantly monitors each S.M.A.R.T. attribute (and its change dynamics) and starts continuously warning the user as the drive degrades. On the initial stages of drive degradation, the user will receive notifications of the Warning type, then Failing (means that this drive parameter is in a pre-failure state) and only then Failed. Learn moreDrive Self-tests
DriveDx allows you to start and control diagnostic self-tests of SSD / HDD. The primary goal is to quickly identify if the drive is faulty. Usually self-tests consist of a collection of test routines like electrical and/or mechanical performance tests as well as the read performance test of the drive. Depending on self-test type it does read scan of a small area or the entire media. Learn moreModern SSDs and HDDs Support
When evaluating the state of various drives, DriveDx can use different heuristic algorithms depending on the drive model and even its firmware version. One of the key advantages of the software is that the state of HDD and SSD drives is assessed using different algorithms, since many state indicators of HDD drives are not applicable or make no sense for SSD drives.Automatic E-mail Reports
The user can get problem notifications and drive status reports to email. Reporting can be configured on the basis of various criteria. Thanks to this feature, the user does not need to have physical access to a specific computer all the time, which is especially useful for all kinds of server rooms, data centers, etc.
A modern, good-looking and user-friendly interface
DriveDx is one of the first drive diagnostic tools created in the true Mac style. All interface elements are clear and intuitive, so it will only take you a few minutes to learn the basics and start using the program. When a problem is identified, you will see a notification on the desktop and the status bar will show the status of your drives. Learn moreDrive Key Metrics Evaluation
DriveDx calculates various ratings of the current status of key drive characteristics (percent values):- SSD lifetime left indicator (in case of an SSD drive)