When I tried to turn of file history I was greeted with this warning message:

"File History has found files that are encrypted with Encrypted File System, are on a network location or are on a drive that doesn't use the NTFS file system. These files won't be backed up".

The file history settings are to "Copy files from: libraries, desktop, contacts, favourites, and Skydrive"

How do I determine which one of the 3 possible problems is the actual problem in my case?
How do I determine which files are not being backed up?

I have turned on file history in spite of the initial warning message. Now the warning message is no longer there so I don't know if it is still an issue.