If you would like to do a 100% clean install of Guitar Pro 6 on a Windows PC:
First begin by uninstalling Guitar Pro 6.
Then run the GP6 Cleaner which you can get by clicking here:
Windows 10: http://www.guitar-pro.com/media/download/GP6Cleaner-Win10.x.bat
Make sure you run it as administrator. (On Vista or Windows 7, right-click on the GP6Cleaner icon and choose “Run as administrator”.) You can then download the latest Guitar Pro 6 version and install the software.
If you would like to do a 100% clean install of Guitar Pro 6 on Mac:
Please begin by un-installing Guitar Pro (you just need to drag the Guitar Pro 6 software from your 'Applications' folder into the trash); then run the following application: