How to unlock folder with red dot imac in Catalina?

Since the latest security upgrade totally screwed up my iMac and I've had to rebuild it from scratch... I need to restore files from my back-up but what was an ordinary folder in Documents is now locked with a red dot -. How do I unlock it to access my files? Get info > permissions only says "Fetching..." and can't be changed. Please advise. Thank you.