Who can resolve conflicts    All users currently editing a shared workbook have equal authority to decide which changes are kept and discarded. The last user to save a conflicting change sees the Resolve Conflicts dialog box.

Why a change can affect other changes    If you accept a change that deletes a row or column, for example, other changes involving that row or column may be affected. If the row or column no longer exists, data that was entered or edited in that row or column in separate changes also no longer exists, so the additional entries and edits are affected.

What happens to changes you don't keep    Rejected changes are recorded in the change tracking log, including a record of any additional changes that were affected. In the History worksheet (History worksheet: A separate worksheet that lists changes being tracked in a shared workbook, including the name of the person who made the change, when and where it was made, what data was deleted or replaced, and how conflicts were resolved.), conflicting changes that were kept have "Won" in the Action Type column. The row numbers in the Losing Action column identify the rows with information about the changes that weren't kept, including any deleted data.

What if you change your mind    You can display the History worksheet and look up the information about the change. Then you can either make the change again, or if the change involved deleting data, copy the data from the History worksheet back to the original location.

Design shared workbooks with per-user protection    Before you share a workbook, use the Protect Sheet command (Tools menu, Protection submenu) to authorize each user to edit in a separate area of the worksheet. Users can receive and view changes to areas they aren't authorized to change, but can only make changes to their own designated areas, so conflicts can't arise.

Assign each user an area to work in    Conflicts occur only when two users make changes that affect the same cell. To make entering lists (list: A series of rows that contains related data or a series of rows that you designate to function as a datasheet by using the Create List command.) easier, Excel allows more than one user to add data to the row at the end of a list without triggering conflicts. If users avoid each other's areas, conflicts won't arise even if you don't use worksheet protection to enforce separate work areas.

Appoint one user tie breaker    If one user frequently generates conflicts, have the user turn off the Resolve Conflicts dialog box, so that their changes always happen.