For some reason, all my Photoshop files are now unable to open in 2025. They try to open 2024, but that no longer exists. I can open PS 2025, access the file, and save it again, but it always tries to open PS 2024.
Even if I go through and tell the file to open in PS 2025, it won't do that.
File associations can be lost in an update if you have "remove old versions" checked.
The problem is that the installer removes the old version after the new one is installed, orphaning the file associations on the way out. When an application is uninstalled, file associations should normally be returned to the operating system.
Usually file associations can easily be re-assigned in Windows Settings, but sometimes that doesn't work. Then an uninstall/reinstall will usually fix it.
To avoid this in the future, manually uninstall the old version before installing the new. If you observe strict version order both ways, this will never be a problem.