Have you seen this error ?
This error message appeared on my computer couple weeks when I was trying to create a new folder on desktop or save network file. Basically, I couldn’t create any files on disk at all. Even I removed the disk and user quote on the server, I still couldn’t create any new files. Fortunately, I found a fix for it. Browse to start, Control Panel, Sync Center, Offline Files, Manage Offline Files (left hand side), Disk Usage tab, Change Limits (Windows 7 64bit)
As soon as I increase the disk usage, I can create and save files again !