Hey, I downloaded the "more columns" mod for CAS, and it broke the CAS (the columns weren't showing up at all), guess I had the wrong update. So I desinstalled the mod, but the CAS is still broken. Does someone knows if there is a way to fix that ?

Try deleting your Localthumbcache file (in The Sims 4 folder)
and if it doesn't work try a folder refresh and/or repair your game

for further notice, make sure you check the dates (and possibly the comments too) of whatever it is you're downloading
the creator of this mod moved from MTS long time ago, and the version here is outdated

the current version is on his Patreon, where he posts nowadays..
https://www.patreon.com/posts/more-columns-in-27751117

Thank you for your answer,
I tried to delete my localthumbcache file, but it didn't worked.

I would like to do a folder refresh or repair my game, but i'm not sure how that work. Can you explain, please ?

I fixed it, there was a file from the mod hiding somwhere.

Will pay more attention next time.