If the workbook is shared, you won't be able to merge or unmerge cells.
That's one of many features that aren't available:

http://office.microsoft.com/en-ca/as...010801033.aspx


Susanstef wrote:
the merge cells option is deselected. that is, I can't tick or untick.
it is currently ticked (but greyed out).




--
Debra Dalgleish
Contextures
http://www.contextures.com/tiptech.html