Mail Merge Fails to Open XML Converter

After updating to OS Mojave, Microsoft Word (v16.18) cannot open any Mail Merge documents or perform a new Mail Merge (setting up a new form document, "Use Existing List"). A second after launching the operation to start the list conversion a "Microsoft Error Reporting" window pops up indicating that the XML Converter (list in Microsoft Excel on same HDD) malfunctioned. Documents can be opened by removing all merge data and header info, but cannot be used as or made into mail merge documents.

I chatted with Microsoft Tech Support the day of the update, and they could not figure out the problem either. After taking control of my screen and going through their procedures, their only advice to me was to uninstall and reinstall Microsoft Office and/or to uninstall OS Mojave and reinstall the previous version of OS that worked with mail merge documents. Have not heard back from them as of today.

Not sure why that specific feature has been effected by the update to OS Mojave, but it is quite irritating and really hampers our productivity. Most of our forms and documents use mail merge.

Has anyone else had this problem? Apple: Have you started to work out this problem? How do I use the mail merge functionality of Microsoft Word with Mac OS Mojave?