If you are having an issue with activation in Studio One, first trash the Plugin Alliance folder in:
%USERPROFILE%\AppData\Roaming\
Then, go ahead and delete the Studio One Preference files in the following folder:
C:\%USERPROFILE%\AppData\Roaming\PreSonus\Studio One 3\x64
Look for the following files to delete:
- PluginBlacklist.settings
- Plugins-en.settings
- VstBlacklist.settings
- Vstplugin.settings
After doing this, go ahead and reboot Studio One, and you should be able to reactivate your plugins without any issues.