We have an Excel shared workbook created by an Office 2010 user and shared among 2 more users both with Office 2007. It seemed to have been working fine for a couple of months, but now we have some issues. First of all, after one of the 2007 users saves and exits, when he brings the file back up his changes are gone. Secondly, the other 2007 user has been getting "The file is locked. Try command again later" when she tries to save or even exit without saving. She can get this error for minutes or for hours. Third, the 2010 user was given an error stating that someone else had saved the file & his changes were going to be lost. This probably happened when one of the 2007 users (me) got an error saying that Excel had to close, then it closed & reopened itself. Any ideas?