I am running CommVault backup using VCB to mount my virtual machines. On the whole, this works fine, but I am having problems with two VMs. They both appear to mount successfully, showing up in the mount volume on the VCB server. The backups, however, keep stalling at 5% with VirtualCentre reporting "Renew disk lease" on each of them every minute.

Can anyone tell me why this is happening?

VirtualCentre 2.0.2, VCB 1.5.0.2192