You can explain it to the user like this for better clarity and safety:
Please back up any relevant data first, then exit UniFab and delete the following folder:
C:\Users\User\AppData\Roaming\UniFabAI\UniFab\data\subtitle-editor
Once the folder has been deleted, restart UniFab.exe and check whether the issue has been resolved.
We recommend making a copy of the subtitle-editor folder before deleting it, in case you need to restore the original data later.