I keep having to reinstall photoshop to my mac and have lost all my preferences

If your system is regularly backed up, you can get all Photoshop settings back from any backup version before the time Photoshop had to be reinstalled.

To find out where they are, like specifically actions, presets, brushes… refer to this Adobe web page that lists their locations for both macOS and Windows.

https://helpx.adobe.com/photoshop/kb/preference-file-names-locations-photoshop.html

Although it’s a long list, notice that most of them are within the same parent folder, so if for example if you’re on a Mac and you restored just the folder…

Users/[user name]/Library/Preferences/Adobe Photoshop [version] Settings

…from your backup, that one folder would contain most of the Photoshop settings files.

How to I keep it from happening again

That part I’m not sure about, because it’s unusual for Photoshop to not open multiple times.

Same problem. I think my updates are not getting interrupted and corrupting the app. shouldn’t happen.I couldn’t open PS today and the icon shows the prohibited sign. When I looked at the site an update was stuck at 49%. I had to cancel it and install again. That shouldn’t happen.

Duplicate. No way to delete.

Do you have an app installed that automatically "cleans" your computer?

something on your computer (typically security software) is corrupting needed files.