My iMac won't restart with option option key held down so I can switch start-up disk to open Windows 10. It just goes black.
Trying to start up in target mode (holding T key down) just gave a black screen then a strange lightning flash icon moving like a screen saver.
Windows, Windows 6
Spoke to Apple - sounds like another Catalina problem. I am running macOS 10.15.1 on a late 2014 iMac. Unmounting and unplugging external drives including my TimeMachine disk solved the problem. A bit of a nuisance to have to do that every time though!
Spoke to Apple - sounds like another Catalina problem. I am running macOS 10.15.1 on a late 2014 iMac. Unmounting and unplugging external drives including my TimeMachine disk solved the problem. A bit of a nuisance to have to do that every time though!
restart
