Customer has slow backup since SMB1 enabled on file servers

Hi,

I've got a customer running BE15 with latest patches, on a 2012 R2 HyperV setup. Backup Server is physical, also 2012 R2, and everything is on a 10GbE connection.

Total size of the 2 VM's for file servers is around 630GB, which used to take around 1 day to complete, however we had to enable SMB1 in order to get some other software to work, and this has now almost tripled to around 3days. Can I account this change in speed solely to the SMB1 being enabled. The other SMB versions are still running.

If so, is there a way of telling BE to use a specific SMB version?

Regards

Michael