Are you using a mail merge main document that has already been set up
for this data source (i.e. you just alter the selection criteria?) If
so, could you have set up a selection criterion such as
name <= "D"?
If you are using Word 2007 and the Filter option, it would be difficult
to miss that, but if you're not familiar with the "Advanced" options
that do the same thing in Word XP/2003 then it may be a bit harder to find.
Or you could go to the Visual basic Editor, open the Immediate box
(ctrl-g) and enter
? Activedocument.mailmerge.datasource.querystring
to find out what query is being run.
Peter Jamieson