From Help on shared workbooks.............

Resolving conflicts When you save changes to a shared workbook, another
person who's currently editing the workbook might have saved changes to the same
cells. In this case, the changes conflict, and a conflict resolution dialog box
appears that allows you to decide whose changes to keep.

........................

Perhaps users are ignoring this and saving just their own changes?


Gord Dibben MS Excel MVP

On Wed, 28 Nov 2007 09:18:06 -0800 (PST), wrote:

Does Microsoft acknowledge that it is possible for users editingdatain the
same field at the same time can overwrite each othersdata?