MSFS does NOT block the community folder, nor the packages folder at all (I do move contents of this folder all the time!). This is entirely a problem of your windows setup and not having the correct permissions.
Main reason for that could be, that you do not have the correct access rights. Per default, as a normal user, you do not have access to the folders where the apps are installed (no write access). To do so you need to be admin.
Therfore as @anon44786522 already mentioned, installing the data files to the app folder on c: is not that of a good idea.
regarding the error, search the forum, this might help you: Error code 0x80070102