If you are using System Center 2012 Virtual Machine Manager Service Pack 1 (SCVMM) to manage storage and assign LUNS, there is a collection of updates that may improve this functionality. These updates are for Windows Server 2012 and need to be applied on hosts, VMM servers and any other system that will interact with storage.

These updates are offered via Windows Update (see KB2785094) but you can also download a standalone installer here: http://www.microsoft.com/en-us/download/details.aspx?id=36259.

Cheers,

Marcos Nogueira azurecentric.com Twitter: @mdnoga