On Win10x64 on an NTFS file system SSD drive.
I had an existing directory with 8 iZotope plugins in:
C:\Program Files\VstPlugins\ (note the capitalization)
When I ran Waves Central v12.0.11 for the first time to install Waves SoundShifter v12.0.0, it seems to have overwritten that VST directory with another directory that uses different capitalization:
C:\Program Files\VSTPlugIns\
This new directory has no iZotope plugins and only the WaveShell2-VST 12.0_x64.dll file.
I think this may be a big problem for all users!!