Has your jumplist suddenly gone missing? Do you have a list of other jumplists for IE and other programs, but not Windows Explorer? If it not letting you pin folders and other programs try this.
Click 'Start'
type '%AppData%\Microsoft\Windows\Recent\AutomaticDestinations' if any of the files are larger than 1mb (1,000 kb) delete them.
Restart
Enjoy pinning files again.
