Unable to launch Apple Diagnostics

A recent development might provide another option:

Apple partners with Best Buy for expanded repair service - Apple

Although the Apple press release makes it sound like the Best Buy program is all on line ("With nearly 1,000 Best Buy stores across the US now providing expert service and repairs for Apple products…."), I just had a chat with an Advisor, who told me: "It really depends on the stores, the agreement is complete, and once they have finished the necessary trainings then they will be added to our providers list." So for instance, my local Best Buy (60 miles closer than the Apple Store) is not yet on the list, but will eventually be listed as an Apple Authorized Service Provider. YMMV, of course.

I'm guessing a little bit here, but I suspect that what has happened is that Apple updated the EFI firmware to only launch applications which have been cryptographicly certified. This is a general security thing that everyone has needed to do. If I am right, that also explains why the thumb drive mechanism also stopped working (because the old diagnostic code isn't certified).

If this is the case, you don't want to back the firmware change out.

I'm out of time to research this tonight, but EFI firmware on PCs has an option in the BIOS menus that lets you turn this on and off. I don't know what Apple's replacement is for EFI, but there should be some way to boot into EFI, turn the switch off to run the diags and then turn it back on again...

Hmm, this is odd.

Obviously you've checked that you have the latest High Sierra update. Also, that you have an internet connection during the "D" key or option+D startup.

There has definitely been an update to how these Macs access the hardware test. I've checked it on two Macs and both are able - for the first time - to access the new Apple Diagnostics service that was previously only available to newer Macs.

This access is through recovery boot, before any OS or account specific settings can load. It's definitely either a firmware update or an Apple server side access permission that has fixed this problem.

I expect the installer for the upcoming MacOS 10.15 Catalina (next month?) will also do an EFI conversion on older Macs such as these Ivy Bridge models. When it appears, I plan to install it on my 2013 MBP to see if it fixes the EFI. Of course, you don't have to stay with Catalina; if it fixes the EFI, you can then erase and reinstall whatever earlier OS version you prefer, e.g. Sierra. As has been noted, doing so does not revert the EFI, which remains as upgraded by the later installer.

I can't run AHT or AD on an iMac13,3 (early 2013) running the latest Mojave. I get the same "Cannot Load 'EFI/Drivers/TestSupport.efi'" error. Additionally, the serial number is now missing (see my post here).

I took it in to an AASP so we'll see what their hardware test yields.

I have a bunch more iMac 13,3s at work (that have their serial numbers!) and I'll try AHT/AD on them tomorrow to see if they have the "Cannot Load 'EFI/Drivers/TestSupport.efi'" error. All of the other iMacs are running the latest High Sierra.

Brian

Same here. I have a late 2012 quad-core Mac Mini Server running 10.14.6. It stopped being able to run diagnostics after a firmware update a while ago. Booting with "D" held down puts up the message "Unable to run diagnostics - DEC 500." Booting with option-D does not work either. I tried the GitHub solution from a bootable USB stick and also from a bootable HD partition. Both attempts flashed some command lines then booted into a different volume (not always the main HD volume).

I am resigned to being a legacy Mac owner stuck in a time warp. I hate giving up a Mac that is working perfectly fine, and which has Firewire 800 and all the other ports I prefer, to settle for a newer Mac that doesn't include decent I/O options. Apple has really gone down a rabbit hole with USB-C, at least until someone makes a USB-C / Thunderbolt 3 hub that lasts more than 4 months before frying out.

MacHound wrote:

750+ is too small of a number for a global company to notice. 750,000 might get their attention, or maybe not.

I don't know where the 750+ number comes from (this thread says 443), but in any case Apple does not monitor these discussions. If you want to bring something to Apple's attention, you must do so proactively. The way to do that is to take your Mac to an Apple Store Genius Bar or an AASP (Apple Authorized Service Provider – note that Best Buy stores are now AASPs), and show them the problem. If your Mac passes their in-house hardware test, then you have a case and can ask them to fix this problem, or tell you how to fix it. If your Mac doesn't pass their test, you'll have to get it repaired before they'll listen to you about this problem.

So far as I know, nobody here has done this. (I haven't due to chronic illness which severely limits my activity.) Complaining here may provide some satisfaction, but does nothing to solve the problem. And it's certainly been established by now that none of us can solve it; it has to be done by Apple.

See my previous (lengthy) posts in this thread for more details.

Ah yes, MBP 2012 needs an ASD, it's pre-internet HWD, might ask for other clues on my site...

https://x704.net/bbs/

I encounter the same problem.

And it's sure Mojave causes that.

Safeboot or Downgrading macOS doesn't work.

We should wait Apple fixes the bug.

https://discussionsjapan.apple.com/thread/250264452

An alternative test to determine the viability our HDs would be helpful in ascertaining the problem. If our HDs are healthy, then we pretty much know that it's a firmware problem related to updating.

Other HW tests include TechTool Pro & SpeedTools Utilities Pro...

No guaranty on how the Disk Tools workm with APFS though.

Nonsense. You don't understand anything about this issue.

The link you gave here makes nothing.

The newest BootROM prevents the Ivy Bridge Macs from running AHT.

Any AHT. You see?

it's Apple's fault.

Can you confirm OS and firmware version on machine where it works and doesn't work please ? (In system information if it boots - or can be done from terminal or Single User Mode if not). Ta

does not work.