Getting is damaged on almost everything after Catalina upgrade
I just upgraded from Sierra to Catalina and every DMG I download, gives me an error like this:
At first I thought the particular app didn't support Catalina until if happened with a half dozen or so apps I tried to download.
And, I get this error when opening .PNG files created from taking a screenshot (shift+command+4). More specifically, if I take a screen shot I can open the .PNG once. If I close the PNG and try to open it again, I get the above error.
If I do an xattr -cr on the file in the terminal window, then I can open it, but that's going to be extremely tedious as I use screenshots frequently.
Textedit files do not seem to have this problem.
I tried logging in as a different user and the behavior is the same.
Does anyone have any suggestions on how to resolve this? Thanks much for any help anyone can offer!
MacBook