I have used C:\Data for some time as a location for storing user data. In build 14316 it gets replaced by a new MS folder. See this (rather obscure) Windows Dev Center post: https://msdn.microsoft.com/en-us/win...shared-storage . An existing C:\Data was copied to windows.old during the update. There have been a few Feedback Hub posts about this and I'm very surprised that MS would use such a simple directory name on C.

Forewarned is forearmed! This may be in the big "Anniversary Edition."