I encountered this issue while playing with profiles in Microsoft Windows. If it so happens you are trying to follow any of my previous guidance which requires editing the contents of %appdata% via its GUI, you may find that game directory locations are not kept.

Should you encounter this error, short of disabling UAC (which you should never, ever do btw) open Mojang's Unified Launcher as an administrator and make changes to game directory for affected profiles. Next time you open it as a standard user you'll see your changes to path for game directory in affected profiles were saved and are in effect.