Mac issues can occur for a variety of reasons, but in general most errors can be traced back to unstable software. The best way to prevent problems from cropping up is to make sure you are using the latest versions of Apple's programs and third-party applications.

macbookairtrio
However, if you've troubleshooted software and the problem persists, it's time to consider whether it's your Mac's hardware that's at fault.

Disk Utility is the first program you should fire up if you suspect disk errors or permission issues, but if that fails to identify the problem or you can't even get your Mac to boot up into the operating system, you can try using Apple's integrated Mac diagnostics tool.

Apple Diagnostics is built into every Mac released since June 2013. If you have an earlier Mac, the equivalent is called an Apple Hardware Test (AHT), but the basic principles are the same.

thunderbolt3ports
To start using Apple Diagnostics or AHT, first turn off any firmware password if you're using one. Next, shut down your Mac, disconnect all external devices except keyboard, mouse, display, and any Ethernet connection, and then follow the steps below.

  1. Press the power button on your Mac and then immediately press and hold down the D key on the keyboard. (To start Apple Diagnostics over the internet, hold down Option-D.)
  2. Release the D key when the prompt appears on the screen asking you to choose your language using the arrow keys.
  3. Join a local Wi-Fi network if prompted.
  4. If your Mac is a pre-2013 model, you'll be given the option to "Perform extended testing," which essentially checks every block of your Mac's memory. Select this option if desired and click the Test button. On post-2013 Macs, simply select the Test option.
  5. Wait for the progress bar to fill while a scan of your Mac's hardware is performed. On newer Macs this usually takes at least a couple of minutes, but AHT can take a lot longer, especially if you chose extended testing.
    checking mac

  6. Once the scan is complete, a list of any potential hardware issues will appear on the screen or a "No issues found" message will be displayed. Note any issue reference codes before continuing.
    diagnostics issues

  7. To repeat the test, click Run test again. For more information about an issue, click Get Started. Otherwise you can click Restart or Shut Down to exit diagnostics.

If you click Get Started for more information about an issue that Apple Diagnostics has identified, your Mac will boot into macOS Recovery Mode and display a web page asking you to choose your country or region.

Click Agree to send to send your serial number and reference codes to Apple, and follow the onscreen service and support instructions. You can also check any reference codes you noted down against Apple's official code table for more information.

Popular Stories

iPhone 17 Pro 34ths Perspective

iPhone 17 Pro Launching Later This Year With These 10 New Features

Sunday March 23, 2025 10:00 am PDT by
While the iPhone 17 Pro and iPhone 17 Pro Max are not expected to launch until September, there are already plenty of rumors about the devices. Below, we recap key changes rumored for the iPhone 17 Pro models as of March 2025: Aluminum frame: iPhone 17 Pro models are rumored to have an aluminum frame, whereas the iPhone 15 Pro and iPhone 16 Pro models have a titanium frame, and the iPhone ...
iOS 18

iOS 18.4 Expected Next Week - Here Are the Release Notes

Friday March 28, 2025 2:01 pm PDT by
With the second release candidate of iOS 18.4 that Apple seeded out today, the company finally provided us with release notes that give a full rundown on what to expect. There's an Apple Vision Pro app, new Apple Intelligence features for notifications and additional language support, plus an Apple News Food feature for Apple News+ subscribers, and several updates that should improve the...
Magic Mouse Green

What to Expect From the Magic Mouse 3

Saturday March 29, 2025 10:15 am PDT by
Apple is reportedly working on a new Magic Mouse. Below, we recap what to expect. The two key rumors for the Magic Mouse 3 so far include a relocated charging port, along with a more ergonomic design. It was briefly rumored that the Magic Mouse 3 would also feature voice control, but that was misinterpreted information. Relocated Charging Port While the Magic Mouse switched from...
top stories 2025 03 29

Top Stories: WWDC 2025 Announced, iPhone 17 Pro and iOS 19 Rumors, and More

Saturday March 29, 2025 6:00 am PDT by
Apple's big developer event is a little over two months away, and rumors about what we can expect to see in Apple's next major operating system updates are becoming increasingly frequent. A public release of iOS 18.4 is also imminent with a number of updates and improvements, although we won't be getting the major Apple Intelligence Siri upgrades that had reportedly been planned for this...
Foldable iPhone 2023 Feature Homescreen

Six Things to Know About Apple's Upcoming Foldable iPhone

Friday March 28, 2025 3:54 pm PDT by
We've been hearing rumors about a foldable iPhone for almost a decade now, but it looks like we might finally see the device come to fruition in 2026. We're going to be waiting many more months for the foldable iPhone, but so far we're hearing good things. Apple wants to make it creaseless. It's taken Apple multiple years to design a foldable iPhone that it's satisfied with because Apple ...
iOS 19 visionOS UI Elements

Apple Codename Provides Clue About iOS 19's Rumored New Design

Sunday March 30, 2025 6:40 am PDT by
Multiple sources have claimed that iOS 19 will introduce a new design with more translucent buttons, menus, notification banners, and more, and there is now another clue that points towards this glass-like appearance. Bloomberg's Mark Gurman today said the new design project is codenamed "Solarium" internally. A solarium is a room with glass walls that allow in plenty of sunlight, so this...
Facebook Feature

Facebook's New iPhone App Feature Turns the Clock Back to 2007

Thursday March 27, 2025 1:59 pm PDT by
In the mid-to-late 2000s, Facebook was all about staying connected with friends and family. However, as the social media platform added new features and grew over time, that core experience began to get drowned out. That changes starting now, according to Meta, which today introduced a new feature that will "bring back the joy" of classic Facebook. Specifically, Meta has redesigned the...
Foldable iPhone 2023 Feature Homescreen

iPhone Foldable Display Said to Feature iPad-Style 4:3 Aspect Ratio

Friday March 28, 2025 3:44 am PDT by
Apple's upcoming "iPhone Fold" will feature a foldable screen with a 4:3 aspect ratio, according to a Chinese leaker who previously leaked the book-style device's display dimensions. The Weibo-based account Digital Chat Station claims that Apple will adopt a "roughly" 4:3 aspect ratio on the inner display in order to achieve consistency between the outer display, as well as to ensure parity...