Once you’ve done that, you’ll see a bar showing the progress of the diagnostic tests, which should take only a few minutes. (If that doesn’t invoke Apple Diagnostics, try again, holding down Option-D to attempt to start Apple Diagnostics over the Internet.) Keep holding down until you see a screen asking you to choose your language. Once you’re ready, turn your Mac on while holding down the D key.

If you’re testing a laptop, make sure it’s on a flat, well-ventilated surface.

Disconnect all external devices with the following exceptions: the keyboard and mouse or trackpad, display, Ethernet cable if you use it, and power adapter for laptops.

If possible, pick a situation when the Mac is most likely to experience the problem (such as right after turning it on for the day, or when it’s unusually warm).

If you have a firmware password enabled, turn it off before proceeding.It tests numerous internal subsystems in your Mac, including the CPU, memory, and firmware displays and graphics adapters connectivity via USB, Bluetooth, Wi-Fi, and Thunderbolt batteries and power adapters on laptops and more.īefore you run Apple Diagnostics, prepare your Mac with these steps: (On Mac models released before June 2013, Apple instead included a similar set of diagnostics called Apple Hardware Test.)Īpple Diagnostics is a set of hardware test routines that Apple bakes into every Mac.

If your Mac is acting up and you suspect a hardware problem, there’s an easy first step that you can-and should-try before calling for tech support: Apple Diagnostics.

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