I'm new to apple, and finally got my second hand iMac booted. I try to connect an external display to the iMac with an mini display port adapter. I have 2 adapters, 1 does nothing, the other makes my external display working (FHD and 4K), but then, the iMac reboots.
I think this has something to do with the switching of the graphics adapter. I searched for a workaround to disable the AMD graphics adapter, but can't find this.
Does anyone has another solution, or tips for a work around?