In some cases, the relations that exist between files in your source CRM aren't supported by your target CRM and therefore can not be migrated.
As an example, assume you have files such as PDFs or documents related to oppurtunities in your source CRM, and during your migration, you would like to transfer these files along with oppurtunities to your target CRM. However, your target CRM doesn`t accept this type of relation between records, and your files are rejected.
To resolve this issue, we simply create a note during the migration process for the specific oppurtunity, and import the related file into this note. This way, you will have all your related files shown with your deals as was in your source CRM, though in your target CRM, they will be directly related to your opportunity notes.