Imac 2020 27'' screen goes blank crashes when connected to an external monitor

Hey Khizarhamid,

It sounds like you are experiencing kernel panics (where your iMac will restart and then display a message that it restarted because of a problem) when your iMac is connected to an external monitor. You can read more about kernel panics and steps to isolate the issue here: If your Mac restarts and a message appears

You can also see if it's possible if your external monitor may have any firmware updates available, to see if that might help.

Take care.

Khizarhamid,

We appreciate that additional information. Since you are encountering a kernel panic, you'll want to check out both of these articles for steps to take:

• If your Mac restarts and a message appears
• If your Mac restarted because of a problem

Have a great week.

Khizarhamid,

Thanks for letting us know. It sounds like you aren't seeing a message about an unexpected restart once your iMac turns back on. We do want to let you know that macOS 11.2.2 was released, if you haven't already, you can try backing up your data and updating to see if that may help.

To confirm, all cables and adapters were plugged in firmly? If anything was loose, it may cause issues. If the issue continues after trying multiple cables, adapters, and after updating macOS, you can contact Apple Support for further assistance here: Contact Apple Support

Best wishes.

Khizarhamid,

Got it. It's important to get this issue resolved, so that you can use your iMac and external display without any issues. Since you continue to encounter this issue after all those steps, you can contact Apple Support for further assistance here: Contact Apple Support

Cheers.

Apple store changed the logic board of my imac. When I got it back, and it works great for several days with my second monitor, however since last Monday (Apr 5), it restarted twice.

issues:

1. Green color for the second monitor,
2. black for imac, and it will be automatically restarted after a while, or you have force shut down it and reboot it again.

I contacted apple support, and they let m send my imac to the store, this is my fourth time to bring my imac to apple store. I don't know what they will do for this time.

It is very frustrated and very bad experience for this imac (2020 27'' imac with 5k)

Have you resolve this issue?

I have almost the same issue (2020, 27inch, imac, 5K), and connect to second monitor, it will be random restarted or frozen. the second monitor turns green, and imac is black. I tried three monitors and two cables, the issue is happened.

When you bought your imac? Have you contact apple support to check your imac?

I sent my imac to Genius Bar, at first time, they told me it software issue, so they just reinstalled my macOX, but the issues are still there, and the second time, they said they can't find any issues, but probably is my user's profile issue, so I gave them my user password, however, they still can't find any issues, and then they just told me to contact Apple Care. Very disappointment for Genius Bar journey.

I contacted the Apple Care last Friday, they collected my data, and told me will take 2 days to get results, which will be this Tuesday and Wednesday. Hopefully they can fix my issue.

BTW, I bought my imac just two months ago, very disappointment for this product. But my MBP is great, and never has issues.

I will keep update this post.