Hi kckay,

You can't reference a non-existant field in a mailmerge, at any level. Doing so will always generate errors when you complete the merge. Accordingly, you will need to either:
• add the field name to all the workbooks; or
• test each source file (eg via a macro) and delete the mergefield from the mailmerge main document before completing the merge.
The second approach, of course, carries the risk that the updated mailmerge main document will then be saved without the mergefield and other merges using that mailmerge main document against data files that do include the field won't reflect that fact.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]