I had this problem, The only way to fix it is to go into user/"username"/AppData/Roaming/ and delete the Slic3r folder. Then reinstall and go through the setup problem, this also applies to the programmed exiting Perl with unfinished threads problem. The problem is Slic3er saves settings to that location, you can remove and reinstall slic3r wherever and as many times as you like but without deleby DionStaiger - Slic3r