Hi,
The note: 529155 - GR for purchase order, M7170 but no batch managemt requiremt says that the message M7 379 is a warning message in standard, and the message category can be changed. If the message is set as warning and still you are getting error message in MIGO, you may check whether any own development is altering the standard behavior or raise an OSS ticket to SAP.
Regards,
AKPT