Unable to open downloaded files
Yesterday I restored a Time Machine backup and since then I can no longer open downloaded files. I get a message that the file is damaged and needs to be moved to the trash. It happens with all kinds of files (PDF, dmg and other). I tried to start up in the safe mode, but that did not help. I see that more people have the same problem, but I have not found a solution yet. How do I resolve this problem
iMac 27″, macOS 10.15