How to use Apple Diagnostics to identify Mac hardware issues

“Apple’s Macs are usually pretty reliable,” Jonny Evans writes for Computerworld, “but when they do go wrong the Apple Diagnostics tool should help you figure out if you have a software or a hardware problem, but you need to know a few things to understand what it says.”

“Apple Diagnostics is designed to put your hardware through a variety of tests designed to detect power supply, battery, graphics, logic board, USB and a huge range of other potential problems. While this test doesn’t cover every eventuality, it’s very good at identifying the most frequent hardware problems you can get using a Mac.”

“You access these tests using a keyboard shortcut when you startup your Mac,” Evans writes. “They are also available via the Internet.”

“The diagnostics code every Mac user should want to see is ADP000. It means no issues have been found,” Evans writes. “That’s good news as it suggests the problem you may be experiencing is not hardware-based.”

Read more in the full article here.

MacDailyNews Take: If you experience an issue with your Mac, the Apple Diagnostics tool can be invaluable.


    1. Do not confuse author Jonny Evans’ “Apple Diagnostics tool” with Apple Service Diagnostics. Actually, the author should have made clear he was talking about the Apple Hardware Test, not Apple Service Diagnostics, which is a much more thorough battery of tests. In addition, booting with Option D keys held down works in my late-2012 27″ iMac, which I received just before Christmas Day 2012. Doing so launches the Apple Hardware Test, which wasn’t delivered to me on an install DVD, as with previous Mac purchases. So if a Mac did not ship with the AHT on a separate DVD or CD, this is the only way to run the AHT on that Mac.

  1. As the article says, there are things tools like this won’t catch, because they perform discrete component checks, rather than run-in-use. My new (at the time) 2012 MBP would eventually hard-freeze if the CPU temps got above 80°C (which happened when the integrated GPU was put to work). Even if it came back down and stayed like that for awhile, it would eventually freeze. Not a nice kernel panic either, which would’ve let the Apple Geniuses see a crash log; no, everything just froze.

    At the store, they ran their diagnostic tests overnight, for 36 hours actually, and didn’t find a thing.

    Thankfully I had a surefire way to reproduce it… after a full OSX reinstall in-store, to ensure no 3rd party software was the cause, I ran the built-in Grapher app and spawned 5 windows actively drawing 3D objects. It hard-froze within a minute.

    After that they authorized a warranty repair, but I hate to think what a less technical user would’ve had to go through to isolate it to their satisfaction.

    1. THIS. I get it that most people don’t ever push computing performance anymore, but those that do are furious at Apple for falling so far behind in real-world usability.

      Whenever someone pushes a Mac processor hard, then the limits of the Jony Ive Get Thin Today Program become blaringly apparent.

      Apple desperately needs to pull its head out and develop a new line of professional Mac laptops and desktops that aren’t restricted by inadequate cooling. The iMac and MacBooks today are marginal at best for sustained operations. And the cylinder, though an interesting concept, is just not an expandable workstation that can keep up with updates that pros want and need. You gotta design with GPU, PCI card, and hard drive/SSD updates in mind. For too long, Apple has acted like its primary goal in Mac design is to put OWC out of business.

      Apple needs to find another design meme, fast. There is a demand, and the Mac would be more profitable than ever, if only Apple invested in it. Shatting out a sealed uniport MacBook netbook is exactly the wrong direction to take the Mac.

  2. Boot Mac holding down  and D to enter diagnostic mode. If you see the code ADP000, you’re fine. If you see anything else, send your Mac into service. (I hope you purchased AppleCare.)

    You can also run the disk utility repair program by booting  and S, then typing fsck -fy without booting the rest of the operating system. (This is assuming you’ve not locked out your firmware with a password.)

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