What if his "c:" drive isnt his primary windows drive would that cause such an error? that thought came into my head since he mention he might have "found" the computer.
edit1: basically my question is, is the program set to download/ install specifically on that drive or is it allowed to be installed elsewhere and if not would it be possible to make a setting for such in the launcher so for one it could become portable (that would be awesome) and two fix his little problem by installing in a place that he does have rights (like My Documents or something)
edit2: It could just be a virus aswell (again the "found" thing pops into mind). I've had a virus on one of my workplace's computers that makes symlinks to nowhere. if his appdata folder was symlinked to a folder he really doesnt have access to or something worse that would produce such error right?