Unity keeps deleting my assets

I’m trying to go through unity tutorial “ruby’s 2d adventure” and it keeps deleting the assets. All my progress is lost. The scene turns pink. Why does this keep happening? I devote so many hours to this long tutorial and it’s all gone. This has happened twice now.

As you can see, my game objects are still there but the sprites are all mostly gone. When I open the folder the assets are not there in the finder either.

Btw, I’ve noticed this happens when there is a new unity version released. maybe it’s related somehow. To combat this I’m going to create the ruby project in a new folder that’s outside of /var and use git to version control everything.

I have the same problem with sprites, anims etc in a project that I have on the backburner. I keep having to copy it back over from onedrive every couple of weeks. I feel like it’s something to do with the link to onedrive but I’m a bit of a noob to pc and can’t make it stop. If anyone has any suggestions I will be eternally grateful.