Strange gmod error

2 days ago, i was playing on sandboxes and spacebuild 3. then, i got tired of the original backround, so I tried to change it to a happyface exploding into a planet. Then i try to play again, and a message comes up. It says “Setup file ‘gameinfo.txt’ doesn’t exist in subdirectory 'hl2”. Check you -game parameter or VCONFIG setting." and i don’t know what it means. I downloaded a different backround, and now when i try to play it, steam says

"Steam was unable to identify your files in for Garry’s mod with a steam cloud

if you have played this game from another computer, your game settings and/or may not be in sync with what is stored in the Cloud. If you play the game now, you might lose those changes or progress"

Can someone help me, cause, I can’t change my filters, so i can’t play any other games besides spacebuild.

That is definitely wierd. Did you try undoing what you believed caused this, in the first place?

I tried, but i couldn’t do it, but the problem kinda solved it’s self. IDK how, it just did.