I'm running Splat Gloucester on 2 machines without issue.
 
One is Win 7, the other is Win 10.

Is anyone seeing the problem I have (combination of Windows 10 x64 and SONAR Producer "G" x64)?
 
My customised Plug-In Layouts have all disappeared from both within SONAR and also in the Plug-In Editor and when I try to get them back (as I have had to do in the past occasionally) by opening them and saving them back, they still don't show.
 
I have also tried completely clean uninstall/reinstall of SONAR including on a new user profile... still not able to get them back. Obviously not a complete show stopper as default lists still available, but does affect my workflow!
 
Have reported it through support, but so far they have not been able to reproduce.
 
SONAR "F" had seemed to work fine after the Windows 10 upgrade (from 8.1). It seems it was only the "G" upgrade that caused my problem.
 
Any pointers (even confirmation that it is not only me) would be really useful.

You can't recover user created data by uninstalling. Where's it going to come from.

Did you press the VST reset button recently? Do you have a backup? If not is the time to sort out your backup situation. Unfortunately removing and reinstalling apps probably won't work. Sorry. Just check your file paths are correctly set up in Sonar preferences.