You are no longer connected to this file. Another user may have removed you from it, or saved over it. To preserve your unsaved ...

You are no longer connected to this file.  Another user may have removed you from it, or saved over it.  To preserve your unsaved work, click OK, and save the shared workbook with a different name. You can then open the original shared workbook again, and merge in your changes from the copy of the workbook that you saved.  For information about merging workbooks, click Help.