Unexpected write conflict error

I have an Access 2003 database with linked tables to SQL on a 2003 server. When a user attempts to save data entered on a form, the error, “This record has been changed by another user since you started editing it. If you save the record, you will overwrite the changes the other user made. Copying the changes to the clipboard will let you look at the values the other user entered, and then paste your changes back in if you decide to make changes”. The buttons Save record, Copy to Clipboard, Drop Changes appear and the Save Record button is grayed. It is a multiuser database, however, there is no other user in the database at the time of error. Does anyone have a solution to this issue? Thanks very much in advance.