Check the name that the file has been given during the merge process. Periods at various places in the name of file will cause it to not be recognized as a Word file by Windows. Some common examples are:

  • Using periods in a date at the end of a file name. For example, saving a mail merge as "Letters 1.25.18". Windows may consider the ".18" as the file extension and format. The file is then treated as an unknown file type and cannot be opened by Word.
  • Using a period in the name file, such using St. for Street or Saint. For example, naming a file after St. Anne Parish may look like "Mailing for St." Windows will consider the period at end of the file name as the file extension. The file is then treated as an unknown file type and cannot be opened by Word.
  • Another variation of periods in the name can occur if it's in the middle, such as "2018Campaign.AnnualAppeal". A period in the middle of the file name is recognized by Windows as an Access document. The mail merge will then create an Access document instead of a Word document.

To resolve the issue:

Re-run the merge. Before doing so, and if you can see the extension, make sure it's .doc or .docx so Word will open.


Right-click on the unknown file, choose Rename, and give it a [.doc] extension. You will then be able to open it in Microsoft Word. (Note: This will only work for a file created without an extension. An Access file cannot be renamed as a Word file and successfully opened.)

Additional notes:

  • NOTE:  If Blackbaud hosts your data, do not change the name of the file in the File Path Location field. Instead, click on the binocular button and change the file name in the 'Save As' window. If you manually change the file name in the File Path Location field, the file will not export as a Microsoft Word file type. It will export as an unknown file type and will not launch the preview of the Word document.
  • If you cannot see extensions (.doc, .xls, .jpg, etc.) on your local computer, then update Windows settings to show file name extensions. (Note: We provide links to third-party websites in an effort to help you resolve your issue. We are not responsible for the information on third-party websites, and we cannot assist in implementing the solution on these websites.)