You have installed Symantec Endpoint Protection (SEP), and are now experiencing various errors when saving file changes from Microsoft Word to a file share.
"Word cannot complete the save due to a file permission error"
"Check the drive to make sure the door is closed and contains the correct disk or CD"
If SEP file system auto-protection is disabled, these errors do not occur.
This problem is fixed in Symantec Endpoint Protection 11.0 Maintenance Release 3 (MR 3).
Upgrade to Symantec Endpoint Protection 11.0 MR 3 and newer.
To download the latest release please read the following document:
Obtaining an upgrade or update for Symantec Endpoint Protection 11.x or Symantec Network Access Control 11.x
See also Symantec Endpoint Protection: Microsoft Word 2000 cannot save file changes to floppy disk or other FAT-formatted volumes