Photoshop 22 saved psd, exported jpg or png files won't open. Error - Can't open file of that type.

I save a psd in Photoshop 22 or above - including latest version. Closed the file. Then tried to open the same file and I get an error "can't open a file of that type." Two different PCs. One is Windows 10, the other Windows 11.  I've also exported jpgs and they can't be opened in Photoshop or any other program. There are no plugins installed. I can, however, open a file made years ago without issue. But if I save it, I can no longer open it.