This behaviour may occur if Word determines that the owner file for the document already exists. This may occur if one or more of the following conditions are true:

  • Word previously quit improperly and, therefore, did not delete the owner file. -or-
  • A second instance of Word is running in the background with the document already open. -or-
  • The document is shared over a network, and another user has it open. From my personal experience, I've found a combination of the first and third point above can recreate this error quite constantly