The common cause for this issue, which usually happens when reinstalling MSFS and restoring it in the wrong way, is the two gsx packages being automatically converted from Symbolic links to real folders, which can happen if you don't know exactly how your backup/restore method handles Symbolic links.
The solution is:
- Remove the two gsx packages in the Community folder
- Start the FSDT Installer and select RELINK, so the proper links will be created as links, which how they are supposed to be.