Although the name has changed to Apple Diagnostics (AD), the purpose of the app has not. AD can be used to find problems with your Mac’s hardware, including bad ​RAM, issues with your power supply, battery or power adapter, failed sensors, graphics problems, issues with the logic board or CPU, wired and wireless Ethernet problems, internal drives, bad fans, camera, USB, and Bluetooth.

Apple Diagnostics Availability

Apple Diagnostics is included on every 2013 or later Mac. It’s installed on the original startup drive and invoked using a ​keyboard shortcut when booting up the Mac. AD is also available as a special boot environment that is downloaded over the internet from Apple’s servers. Known as “Apple Diagnostics over the Internet,” this version can be used if you replaced or reformatted the original startup drive, which erases the AD version that was included at the time of purchase. The two forms of AD are, for all purposes, identical. Although, AD over the internet involves a few extra steps to launch and use.

Using Apple Diagnostics

AD is for Mac models from 2013 and later. If your Mac is an earlier model, follow the previously mentioned Apple Hardware Test or AHT over the Internet. After your Mac turns off, you’re ready to start Apple Diagnostics or Apple Diagnostics over the Internet. The difference between the two is the keyboard command you use at startup and the need for an internet connection to run AD over the Internet. If you have AD on your Mac, that’s the preferred version of the test to run. It doesn’t require an internet connection. Still, if you have one, you can access the Apple help system, which includes diagnostics notes based on AD error codes that may be generated.

Starting the Test

Here’s what you need to do to run the Apple Diagnostics test:

Finishing Up

If your Mac generated errors during the AD test, you can send the codes to Apple, which will result in an Apple support page that shows options for repairing or servicing your Mac.

Apple Diagnostics Error Codes

Compare any error codes that resulted from running Apple Diagnostics with this list: