Yes, you can migrate already migrated files/attachments. Follow these steps:
- Navigate to the Mass File Migrate app and select the "Mass File Migrate" tab.
- In the "Select File/Attachment" dropdown, choose file or attachment according to your requirement.
- Select the object from which you want to migrate files/attachments.
- Turn ON the Toggle "Reconsider already migrated Files"
- Click on the "Search" button.
With this setting, already migrated files/attachments will also show in the table, and you can migrate them again as needed.