Apple Diagnostics Imac

[Glendora Spink]

About a month ago, my wife was using the computer for a zoom meeting and suddenly vertical lines appeared on the screen. An inquiry to a local Mac technician resulted in a recommendation that the time had come to upgrade the computer. We purchased a new Macbook Air, and have made the transition.

Now, I'm readying the computer for sale. I've wiped the hard drive and performed a new installation of the operating system, High Sierra, version 10.13.6. There appear to be no issues with the screen - looks great. But I'm concerned that there might be some underlying problem with the computer, and I'd like to be able to describe this to the buyer of the machine.

I found an article -us/HT202731 describing how to run diagnostics. But I am not successful in running it. Holding down the "D" key on restart, the process results in "Starting Internet Recovery. This may take a while" and then an exclamation point followed by "apple.com/support - 3403D". The same article states:

I called Apple support, and they told me I'd have to bring the machine to an Apple store to have it evaluated. Before I do so, I'd be curious if anyone else has been through this, and what the results were, or whether any solutions might be suggested.

I tried to run Apple Diagnostic by pressing and holding "D" immediatly after running computer as apple documentation says but when I do this I get network selection screen (I didn't press "option" + "D"). But after selecting the network I don't see any diagnostic started. Just the same network selection screen where I can reselect the network. The same goes if I tried to press and hold "option" + "D".

Apple computers ship with a pre-installed suite of hardware diagnostic tools, known as Apple Hardware Test (AHT). In principle you can start them by holding the d key while booting. Newer models support holding option d to load AHT over the internet. Refer to the official Apple documentation for details: Using AHT on Intel-based Macs, Mountain Lion, Mavericks and Yosemite. Apple redesigned the AHT, now called Apple Diagnostics, for Macs introduced after June 2013. Consult the reference codes to interpret the results.

If however, you reinstalled an older computer from scratch, the diagnostic tools might no longer be available. Unless you have the original disks that came with your computer, there seems to be no way to restore the AHT.

It happens that Apple provides disk images with AHT for most computers, but does not make the links publicly available. Various blogs and forums, mostly Riven by Five and MacForum.ro have gathered a list of download links. The rest were obtained by scraping _Hardware_Test/ for all the links of the form 0(1822)-\d4-A.dmg.

Download the AHT for your computer model and use the contents to restore the /System/Library/CoreServices/.diagnostics folder, then reboot while holding d to start the diagnostic tools. Alternatively you may try with a bootable USB stick, as described below. This is also the preferred way on OS X 10.11 or later, where the System Integrity Protection (SIP) no longer allows writing to system folders.

When trying to open an old dmg you may get the error 'legacy image should be converted'. To convert it to a newer format, open Disk Utility, in the menu Images click on Convert and select the dmg to convert and save it under a new name.

Note that there is no one-to-one correspondence between hardware model and AHT. For some models no hardware test could be found, while others seem to have multiple AHT. As the differences are not clear, feel free to try them out, to see which one works best for your hardware.

Yes, I use wireless keyboard but it's connected to my iMac by USB. I don't think that's the problem because keys on my keyboard work while booting (I can open recovery mode). I don't know why I'm getting network selection screen instead of apple diagnostic screen.

Sorry. I posted question from another computer. I'm working on iMac 2020 with Intel processor and Mac OS Ventura 13.3.1. So I don't have AHT. Can reinstalling Mac OS and "erasing all content" (from settings) delete diagnostic folder?

Did reinstalling Mac OS and "erasing all content" in settings delete diagnostic folder (/System/Library/CoreServices/.diagnostics)? Is location of diagnostic folder is the same (/System/Library/CoreServices/.diagnostics)?

If the Apple hardware diagnostics test determines there is a problem and reports an error, you should write down the error code and any provided details (or take a picture of it with your iPhone) so that you can learn more about the problem. Noting the error code will also help to relay information to an official Apple Technical Support advisor or an Apple Certified Repair center. For Macs with Apple Diagnostics, there is a list of error codes found in Apple Diagnostics here on support.apple.com, whereas Apple Hardware Test error codes are a bit more self explanatory for technically inclined, and they can be searched for on the web to determine a potential match.

If the Mac is out of warranty, whether or not you want to take a stab at it or let someone else handle the repair is likely a matter of your technical knowledge and comfort level in opening hardware to manually intervene. The latter scenario is really only appropriate for out-of-warranty computers owned by advanced users with extensive technical know-how, and most Mac users should simply take problematic hardware to an Apple Store or Apple Certified Repair location.

Tried D to diagnose a black screen on startup on 2010 iMac. Reset SMC & PRAM did not work.
Apple diagnostics takes me to Network and when I enter correct network and password, it freezes with spinning disc and would not go to diagnostics. Any suggestion to bypass this?

I had the same problem reported by Megan (above) and others: AHT runs for a while then stops, with the progress bar stuck at 95%. This is on a 2008-vintage MacBook Pro(4,1) that starts booting OSX but then freezes at gray screen w/Apple logo.

For everyone having trouble running AHT by pressing D or Alt-D on boot. You need to download the right version of AHT for your machine from here and just run it off a USB drive on boot (hold down alt/opt), you can find the AHT app on github (user upekkha has compiled all the info you need on there) and follow the instructions. I ran off a USB drive for a 2008 MBP Unibody no probs.

All you trying d command with startup try cmd +d instead as d often the test function gets deleted while restoring your hd or swapping it. CMD +d you will download the test from internet with your wifi.

For everybody where the AHT does not start, on 2010 or older models you have to use the 2nd DVD delivered with your mac and then restart holding D. The AHT Software is on the DVD and internet based is not possible.

Lovely. So those of us who bought a used MBP and did not get the original disks that came with it when new are screwed and cannot do the hardware tests. That sucks and should be something that could be worked around. Instead the brains at Apple made it harder for the end users.

Battery is internal but with a look at iFixIt.com, you can see how to safely remove the thing and replace it yourself if needed for a whole lot less than the Apple people will charge. Did that on my 2011 and our 2010.

Yes this is absolutely true, Apple runs a series of deeper tests from a bootable volume that is separate from the consumer-facing Apple Diagnostics tools. This utility is for the average end user to see if they can detect a more obvious problem, like a failing hard drive.

I ran the Apple Hardware Test (disk came with my iMac) on my mid 2010 iMac and the test could not find anything wrong, yet I am having what I think is a graphics card problem. iMac boots into the grey screen of death and stays there.

Tried holding down D, tried option-D. Both times I got some internet reinstall globe logo that after asking me to choose my WiFi Network and give my password gave me error code 3404-D. Nice. Again. NO point in a diagnostic or test mode that does not work.

Paul, you should have mentioned in your article this will only work with older Macs pre-2013, also once mountian lion has been installed on any pre-2013 it will run apple diagnostics by holding option-D

Just download the right version of AHT for your machine from here and just run it off a USB drive on boot (hold down alt/opt), you can find AHT on github (user upekkha has compiled all the info you need on there) and follow the instructions. I ran off a USB drive for a 2008 MBP Unibody no probs (except the extended test took nearly 3 hours!).

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