How to Use the Apple Diagnostics on your Mac

How to Use the Apple Diagnostics on your Mac

Hello Mac users,
if you have some unusual issues with your Mac and think that they could be caused by hardware, the Apple Diagnostics feature can help you to find the problem and even to troubleshoot it.

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The Diagnostics process runs a series of various tests on your Mac and check all the possible hardware issues. It doesn't look for them in the system and its software, but checks the underlying problems. For example, battery problems, non-working ports, graphic card or monitor issues and any other troubles that are usually caused by hardware bugs are checked by Apple Diagnostics.

I can say that this kind of diagnostics is just another form of the Apple hardware test we used to know before. New Macs from 2013 run Apple Diagnostics, while older versions work only with the Apple hardware test (AHT).
Is it better for a user? I don't know exactly. AHT shows users more detailed information, while Apple Diagnostics is restricted and shows fewer data... However, both of these options are great at troubleshooting issues with the Mac hardware. No matter what Mac model you are using, your problems will be surely solved either by AHT or by Apple Diagnostics.

Entering this feature is fairly easy. You just have to press several keys of the keyboard while your MacOS is booting. Here is a manual about how it should be done...


How to Enable Apple Diagnostics on Your Mac to Test the Hardware for the Possible Issues:

  1. Disconnect all the devices or cables that are plugged into your Mac. Leave only those devices that are necessary for Mac's proper functioning, for instance, a mouse, keyboard, power cable and display will be necessary for the further work.
  2. Shut your Mac down. Visit the Apple many and select the 'Shut down' option.
  3. Turn it on. Press the power button, and then immediately hold the 'D' key.
  4. Continue holding this key on your keyboard until you see the message offering you to select the language. Click the necessary one and proceed further.

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  5. The Apple Diagnostics feature will start its hardware tests series. A progress bar will be shown on your screen, it will also display the remaining time and the message saying 'Checking your Mac'. Usually, it takes a few minutes to run to the end.

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  6. After finishing the whole process, your Mac will tell you about any hardware issues found on your machine. Then, it will display a reference code.

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  7. You can run the diagnostics once gain. For this, choose the 'Run the test again' option. Or, if you don't need this, select the 'Get started' line, or 'Restart', or 'Shut down'.

There is a plenty of potential problem messages that may be shown by Aple Diagnostics. If you are not sure which ones are critical, remember their codes and contact the Apple support. They will tell you what to do further with those issues.

Bear in mind that not all the issues will be flagged by the diagnostics process. Maybe some of them will need some more troubleshooting steps or tests that can be performed in an Apple service center by a technician.
For example, it could be situations when your Mac doesn't start in some cases or it shuts down automatically from time to time. It may be issues with the display or ports. Also, Apple Diagnostics won't show you any physical damage. For instance, if you have your external screen damaged, it won't show that. Damaging of hardware caused by water or any other liquids won't be marked in the issues list.

That's why I can make a conclusion that Apple Diagnostics is not a universal feature, but at least it's great for the start doing troubleshooting. It can easily deal with a few hardware problems on any desktop Mac as well as modern MacBooks.


Running the AD Process With the Internet

Yes, you've read it right.
You can run the diagnostics process through the Internet. Hold down the 'Option' and 'D' buttons during the system start process. This will take more time for loading, but the hardware diagnostics process works the same way.


How Can I Understand the Codes of Apple Diagnostics?

If the feature reports you an issue, it will show a reference diagnostics code and a short explanation of what's wrong with your hardware.
You can note these codes and check them on the Apple official website. it provides users with all the necessary additional information.
I hope this resource will help you in troubleshooting Mac issues.


Going Further With Troubleshooting Hardware Issues

I want to remind you that Apple Diagnostics is a helpful tool, but not a universal and definitive one. Maybe, if you face hardware problems, you may also do the following things except running Apple Diagnostics:

  • Repeat the test for several times.
  • Backup your Mac with Time Machine.
  • Do a SMC reset.
  • Do a NVRAM and PRAM reset.

If the problem is not solved by doing all the mentioned above, contact the official Apple support, or visit an authorized Apple service center for their assistance.

The nice news is that problems with hardware are quite rare, and they are fixable. The even better news is that if you have an Apple warranty or their Extended warranty, you will get the repairs for free. But remember that warranties work only for those cases when the damage is not caused by a user.

I hope you won't face any serious issues with your Mac. But if you do, this article may help.