Some people are getting the Document cache error while playing with their favorite office application. If you are for any reason getting this error, the quick steps listed below will instantly repair the problem.
First make sure that MSOSYNC.EXE process is not running, if so, kill it.
Now navigate to the HKEY_CURRENT_USER\Software\Microsoft\Office\14.0\Common\Internet and delete the FileStoreCriticalError key. If the key doesn’t exist then you can skip this step.
Make sure that the OfficeFileCache folder does not exist in the system. Please check the %userprofile% \AppData\Local\Microsoft\Office\14.0\ path and be sure to delete OfficeFileCache if it exists. %userprofile% is usually C:/Users/[UserName]/.