Apple Hardware Test - MacBook pro 13" Mid 2012

Don't feel alone, many user complaining they can no longer connect to the AHT server.

No resolve.

In or out of warranty you can get a free over the counter 'Apple Service Diagnostics' test /assessment

Make an appointment for a "hardware issue"—

https://www.apple.com/retail/geniusbar/

Are you having an issue that maybe we can trouble shoot here?

Your computer originally came with 10.7.x (Lion) which was the first OS available for download only and, it may be that, unless you installed a firmware update at the time to allow internet recovery, trying to initiate the hardware test may not work correctly. Unless someone comes up with an idea, I'd suggest you take it to your nearest Apple store to have them run their version of (a more inclusive) hardware test because yours is not working.

Apple Hardware test was included on the original drive shipped inside your Mac. It was also on the original Installer DVD, if yours shipped with one of those (I see babowa doubts there was a DVD for that Mac).

If your disk was ever erased or replaced, there is no part of MacOS that makes certain the invisible .diagnostics folder is returned to its special place at:

/System/Library/CoreServices/.diagnostics

Downloading of Diagnostics on demand is a feature of Apple diagnostics, That was featured on Macs issued about 2013 and later. Apple Hardware Test was never downloaded on demand.

A Mac user has collected a lot of the freely-available versions of Apple Hardware Test and made them available here:

https://github.com/upekkha/AppleHardwareTest

The recommended way to proceed today is to create a bootable USB-stick, using the directions found at that site.

Standard RAM:4 GB -- Maximum RAM:16 GB*

Details:4 GB of RAM is installed as two 2 GB modules, no slots free.

*Apple officially supports a maximum of 8 GB of RAM, but third-parties have determined that this model actually is capable of using up to 16 GB of RAM with two 8 GB memory modules.

from:

https://everymac.com/systems/apple/macbook_pro/specs/macbook-pro-core-i5-2.5-13-mid-2012-unibody-usb3-specs.html

.

I've got the exact same model (upgraded to 12 GB RAM and an SSD) and it shipped with 10.7.3 (Lion - no DVD); I've not tested whether the AHT works or not on that. In any case, at the time, I did some extensive testing of mostly iMacs with either Snow Leopard and Lion and found that neither recovery nor AHT were reliable on machines from mid 2010 - 2012 (right on the cusp of the Apple change from install media to download only).

literally all of the above. If I remember correctly, I tested various scenarios on a 2010 and 2012 iMac - several tests (done via recovery, wiping/not wiping the hard drive, and via an external clone). This was right around the time of changing to download only and firmware updates for older Macs to allow internet recovery. What I found was that once the firmware update was installed, the install media no longer worked 5 out of 6 times and, when I filed a bug report, Apple Engineering replied with “working as expected” (in other words, no one was going to do anything about it). On the other hand, internet recovery also only worked (as in it just would either not connect at all, or connect, but nothing worked once you got there). I don’t remember if I still have the report I wrote - after all, that was 8+ years ago - but I will take a look when I have some time.

when you say, "were not reliable" do you men they would not load from your disk, did not load over Internet Recovery, or that they did not find anything when run?

What a great and useful answer. Thank you very much.