Problem importing images / videos to Insta360 Studio

For about 2 years I’ve used Insta360 Studio on my iMac to edit my Insta360 One X images and videos. All worked well.  
Bound at home today I once again tried to import 360 images and video files into Insta360 Studio. But all I got was a blank black or a blank
green screen. Thumbnails of the imported files show up on the left side of Insta360 Studio. Reinstalling the software didn’t bring any differenceSo what’s going wrong?
Great if anyone could help!
All the best for you, wherever you are in this weird Corona World.
Walter