No it's not the C$ stuff -- browsing through C you get messages file does not exist -- it's all ok once you get to users and browse from there.
Absolutely no probs with any other Windows shared drives.
Not that I have heard. The only thing about Redstone that I have heard is around 1200 changes, with a lot in a bad way.
After the last rollout which broke stuff on my test box, 10 got yanked and the discs destroyed. I am done playing with Microsoft and being their Beta tester.
From this point on, it is purely Linux in my house.
I saw that also, until I disabled SMB 1 & 2 on my test box with 10. Once I did, all shares showed up on the 10 box and Linux boxes.
It has nothing to do with UAC. No Registry edit needed.
The Root of the file tree has always been locked down since 7. Only way in by share is to give the User control at that level, which is how malware takes over.