Camera freezing since upgrade to Catalina
Hi
I recently upgraded my Late 2014 iMac 27 inch to Catalina and since then the camera is intermittently freezing with Facetime, Zoom, Webex etc. The green light stays on but the video hangs. Other times you try to activate video and it just shows a grey screen. I've got 16GB of RAM and it's running at about 11GB of usage when the problem is occurring so I don't believe it's down to lack of memory. Anyone got any ideas? I see there are previous threads dating back years where people had similar issues after people upgraded to High Sierra etc... but I can't see any definitive replies about what the cause / solution was. HELP PLEASE!
iMac with Retina 5K display, macOS 10.15