Problems with MAC addresses after upgrading from 5.0 to 5.1

Hi all,

I've just experienced a very anoying problem after the upgrade from vSphere 5.0 to 5.1 succeeded: Some of my VMs cannot be stared due to the fact that their MAC address are NOT in the allowed range anymore. So one of the VMs is running an HP P4000 Lefthand VSA an was assigned the MAC address

00:0C:29:84:12:E4 by vSphere 5.0 and after the upgrade to 5.1 the MAC address is "marked as invalid" and the VM cannot be started anymore. Since the license key for the HP P4000 Lefthand VSA is issued according to the MAC address I cannot "change" it because this would lead to a non functioning product. Also, re-licensing the HP P4000 Lefthand VSA is not an option.

Can anyone help?

Thanks,

Holger