What do I do when my iMac 2019 apple diagnostics hangs with message "waiting for support"? It started fine by holding the D key while starting, went through some initial tests (no report) and asked if I wanted further tests, I said yes.
iMac (2017 – 2020)
This article from Apple related to the Apple Hardware Test ( AHT ) features you are referring to in above question
link below
How to use Apple Hardware Test on your Mac - Apple Support (CA)
Excerpt from above link
This article from Apple related to the Apple Hardware Test ( AHT ) features you are referring to in above question
link below
How to use Apple Hardware Test on your Mac - Apple Support (CA)
Excerpt from above link
That means that Apple or an Apple Authorized Service Provider started a service diagnostic session with the serial number of your laptop and never "archived" the session to release it. It may be that a tech entered an incorrect serial number for a diagnostic session which just happens to be the serial number for your laptop instead of the laptop intended.
Contact an Apple Store or an Apple Authorized Service Provider to start a service diagnostic session for your laptop, then have them "archive" the session which will allow your laptop to access the consumer level diagnostics.
Apple Diagnostics hangs with "waiting for support" message
