When trying to run a Box migration, the following error is shown:

Sharegate.Common.Exceptions.SGNotSupportedException: This document cannot be copied because Box notes cannot be converted to documents within SharePoint.

This error occurs because Box Notes cannot be opened from SharePoint and are not currently converted to a proper document type.

You can add the notes to your destination list in SharePoint by saving them as a PDF, or by copying the content of the notes to a text or Word document and manually uploading the new file to SharePoint.