Don’t do that. It only changes the location of the server program files (which you should keep on drive C:)
Uninstall, then re-install to the default location for program files on C:
To relocate the Plex data folder, you need to change a key in the Windows registry.
See this post for details (make sure to heed the caveats): [HowTo] An extended guide on how to move the Plex data folder on Windows
