In order to avoid known problems during Hyper-V deployments I really encourage you to apply these updates to your environments

Hyper-V V1 Hotfixes list

http://technet.microsoft.com/en-us/library/dd430893.aspx

Hyper-V R2 Hotfixes list

http://technet.microsoft.com/en-us/library/ff394763(WS.10).aspx