Mac crashing when connected to a second screen

[jifferbelle]

Is anyone else having this problem or know how to fix it?

I've got a 2020 iMac updated with the latest Big Sur 11.4, however when I try to connect a second monitor, it works for a while then crashes.
I'm using the bon.elk USB-C to HDMI 4k adapter which is (according to them) compatible and have tried two different ACER monitors and experienced the same problem. I've never had this problem before with my old mac and would rather not buy a new HDMI adapter unless entirely necessary.

Thanks!

 

[chscag]

Welcome to our forums.

Please identify your iMac. Is it a 21.5" iMac or is it a 27" 2020 iMac? We would need that info before attempting to assist you.

Also, we recommend using an Apple adapter rather than a third party one. Your problem does sound like it could be either a bad connector or adapter.