Use Apple Diagnostics to test your Mac

Apple Diagnostics, formerly known as Apple Hardware Test, can check your Mac for hardware issues.

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

  1. Shut down your Mac.
  2. Disconnect all external devices except keyboard, mouse, display, Ethernet connection (if applicable) and connection to mains power.
  3. Make sure that your Mac is on a hard, flat and stable surface with good ventilation.

 


Start Apple Diagnostics

Determine whether you're using a Mac with Apple silicon, then follow the appropriate steps:

Apple silicon

  1. Turn on your Mac and continue to press and hold the power button as your Mac starts up.
  2. Release when you see the startup options window, which includes a gear icon labelled Options.
  3. Press Command (⌘)-D on your keyboard.

Intel processor

  1. Turn on your Mac, then immediately press and hold the D key on your keyboard as your Mac starts up. 
  2. 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:

macOS Diagnostics running progress bar

When testing is complete, Apple Diagnostics shows the results, including one or more reference codes. Learn about Apple Diagnostics reference codes.

macOS Diagnostics results. No issues found.

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 web page 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.
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