Why did my preferences reset?

[NewtonLightcatcher]

I discovered as I was quickly trying to use Lightroom Classic and Photoshop that many of my selected preferences for file handling, naming, image size, pixels per cm instead of inches, were changed. Some things like my watermark remained. I have not gone through both apps to check color space, and my copyright info and metadata settings and info, or if it has done the same to all my computers. Why no warning or permission asked? Why no instruction or way given to save all of this and put it back without spending a lot of time going through the over-complicated menus looking for hidden switches like playing a game?  

[D Fosse · Accepted solution]

If preferences don't stick, it's one of two things:

• a permissions issue in your Windows user account. Preferences and settings are stored in your user account, and Photoshop needs full read/write privileges.
• irregular shutdowns and/or crashes. Preferences are rewritten in full on every application exit. If the application doesn't shut down orderly, writing preferences is aborted and returns to default settings.