When trying to migrate data, the migration fails and the following error is logged:
"* Error * [time of migration] Failed to migrate path:\\?\UNC\Servername\Volume\Folder"
The database may be full, most notably if SQL Express versions are in use. They have a 4GB limit and a large migration may fill it.
Exporting the NDSMigrator database and importing into a more robust version of SQL (or upgrading SQL) is recommended.