I just tried theming, with the same theme packages I used on Windows 8.1 and the Preview up until 100147 and totally
NUKED!!!I think it was the OldNewExplorer.exe that did it. I'll try again in a few months when I finally have vacation for 3 weeks and search around for Win10 compatible stuff. Oddly installing the UXStyles from the preview had absolutely no negative effects that I could see like on Windows 8.
Windows 10 to a black screen and cursor. I had to boot to the recovery partition to run Macrium for a restore.