"Various" means "more than one". You might use a search engine to find one, but start here with Adobe Help. A couple are listed, plus there is a lot of good information on prevention.
This is not a Photoshop bug and a moderator should move it to "discussions".
File corruption is always caused by failing hardware - a failing drive, bad RAM, wobbly cables or connectors, or a power outage in the middle of a save.
This is why we all make backups, and save incrementally during work.
You can try the various recovery software available on the web, but don't expect miracles.