I had the 'blank desktop on startup' bug on only one of the two computers I've upgraded from Win7 to Win10. The 'good' computer was on the latest version of Fences and upgraded fine. I'd not realised the other computer was on 'Fences Pro' which is out of date. I missed it as 'check for updates' in Fences said there weren't any, which was unhelpful. So I accidentally upgraded to Win10 on top of Fences Pro which seems to be a bad idea.
Once in Win10, I upgraded Fences Pro to the latest. It looked OK but as Windows was shutting down, a crash error appeared (unreadably quickly) and the desktop died. On reboot, the startup splash screen and one segment of the start button icon (Start10) isnow a strange orange colour that I can't fix. Fences is fine, though, if I ignore the new orange colour accents here and there !
In summary, make sure Fences is really on the latest version before an in-place upgrade to Win10.