@mphillips_bokf Hello Melody, If this issue was not resolved, please open a Support case by emailing support@nintex.com. We would need more information in order to assist. Thanks!

We verified that there were no duplicate field names so that was not the real issue.  Our company recently upgraded to Microsoft 365 and we are experiencing intermittent errors with Access Db and Excel files.  This particular duplicate field error is no longer happening after the user also reported the repair excel registry error and we did the registry repair.