I had to update to Windows 11 and reinstall iStripper after. I backed up all model files to save you traffic but the program does not recognize the files and wants to redownload everything?

Did i do something wrong? It is not the wrong folder since the downloads overwrite the exact same existing files.

Instead of downloading the files, you can rebuild your collection.
Rebuild will check what files you have, but will not download the animation files.
It will take probably more than a minute for the rebuild.
Do nothing with the app until it is done.

Already did that. Didn't impress that download fetishist ;)

@VirgilTura
Try log out/log into your account via the app with your active login/password.