The latter is easy to check. I have not seen this message before V16. I need this option badly.
Typically, this is caused by a conflict in the Office Driver: 32 bit versus 64 bit.
Have a look at this article: The following link is no longer available. To access this information, copy the title found in the url into the search tool on the top nav bar, or try searching for key words in the post. https://li360.pitneybowes.com/s/article/Unable-to-create-MapInfo-table-from-file-error-message-when-opening-Excel-file-in-MapInfo-Pro-64-bit
Quick workaround is to save to xls rather than xlsx (guessing that the conflict is with xlsx - depending on which version of Office you have installed).
After I (unvoluntarily) reinstalled Windows 7, the EXCEL spreadsheets converted to Tab files flawlessly. Thanks for your help.