You may want to add a note in your User Guide that there is a 37,767 Character size limit in Excel for loading data with MxLoader. Just to help save people some grief in future.
This is a Microsoft limit and has nothing to do with MxLoader. We were migrating Start Centers and spent much time trying to figure out why they were not working. Little did we know of this size limit being hit with no informational messages telling us of the limit being exceeded.
Hope this helps others save time if they hit same issue.