Which version of Word/Excel?
If the "bad" workbook is simple enough (e.g. no formulas, just data, try
exporting the sheet(s) to .csv format and importing them into a completely
new workbook.

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Peter Jamieson
http://tips.pjmsn.me.uk
>I have been using Excel as the data source for mail merge in Word with no
> problems. I have two excel files. One works perfectly well but the other
> is
> now coming up with "Word was unable to open the Data Source" Any
> suggestions welcome