How to Run Apple Diagnostics to Check Your Mac

* This article is from our Tip of the Day newsletter. . *

Apple Diagnostics (formerly named Apple Hardware Test) is a simple test to help you determine if there are hardware issues on your Mac. Whether you're computer-savvy or not, this program will suggest solutions and help find out what's wrong with your Mac.

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Figure out Which Processor Your Mac Has

Your first step is to determine whether your Mac has an Intel or Apple processor. This will determine which steps you follow to run Apple Diagnostics on your computer.

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  1. Click the Apple Menu.
  2. Select About this Mac.

    Click the Apple menu and select About this Mac before running the test.
  3. Look at the line labeled Processor or Chip to determine which processor you have. The example below shows an Intel processor.

    Check to see whether your Mac has an Intel processor or Apple processor.
  4. Shut down your Mac.
  5. Disconnect all external devices except those necessary for computer use, such as your keyboard, mouse, display, Ethernet connection, and power connection. 

How to Run Apple Diagnostics with Apple Processors

Here's how to run Apple Diagnostics on a Mac with an M1 chip:

  1. If you haven't already, start with your computer completely shut down.
  2. Turn on your Mac by pressing and holding the power button as your Mac restarts.
  3. Release the power button when you see the startup options window. 
  4. To run diagnostics, press Command-D on your keyboard.

    Press and hold the Command-D keys on your keyboard to run Apple Hardware test

Related: Troubleshooting 101: How to Fix Your Buggy or Unresponsive iPhone or iPad

How to Run Apple Diagnostics with Intel Processors

Here's how to run Apple Diagnostics on a Mac that uses an Intel processor:

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

    Press D key to run Apple Hardware Test
  2. Release when you see a progress bar showing that the test is running. 
  3. If this doesn't start the diagnostics test, turn off your computer and restart. This time, press and hold the Option-D keys as your computer starts. This will run Apple Diagnostics over the internet.  

    Press and hold Option-D keys if Apple Diagnostics is not running

When testing is complete, Apple Diagnostics will show you the results, which will include at least one reference code. A reference code is a short series of letters and numbers indicating a specific issue or test status. (For example, 'ADP000' means that there were no issues found.) Once you have your reference code, you can check this complete list of Apple Diagnostics Reference Codes to get more clarity on what the issue is. If you need further assistance, you can also contact Apple Support for more detailed service and support options. 

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Author Details

Ashleigh Page's picture

Author Details

Ashleigh Page

Ashleigh Page is an Associate Editor for iPhone Life. A longtime Apple enthusiast with a Bachelor's in English and Computer Science and three years of experience writing about tech, Ashleigh has written and tested hundreds of articles about devices and features within Apple's ecosystem. She specializes in iPhone, iPad, AirPods, and Mac content and has authored a 60-page in-depth guide about the Apple Maps app. Based in North Carolina, Ashleigh is often crafting whimsical (and sometimes nonsensical) short stories and hiking when she's not working.