PVS machines become unregistered.
They are in a unresponsive state and do not respond to ICA, RDP, or Console connections.
Discovered that the PVS target devices were exhibiting massive retries in the Vdisk usage pane:

The default lifespan of ARP cache entries was lowered from 10 minutes in Windows Server 2003 to a random value between 15 and 45 seconds in Vista/W2K8. As a result, the Provisioning Services bootstraps are 20 times more likely to experience a timeout during a Vista/W2K8 boot. The workaround is to increase the ARP cache entry lifespan for Provisioning Services -bound NIC’s, Provisioning Services Server and VDA:
·         Open a command shell window. At the command prompt, enter the following command:
netsh interface ipv4 show interfaces
·         To set the ARP cache entry lifespan to 600 seconds, enter the following command:
netsh interface ipv4 set interface <PVS interface number> basereachable=600000
·         To verify the new setting, enter the following command:
netsh interface ipv4 show interface <PVS interface number>
Note: The Base Reachable Time should be set to 600,000 ms, and the Reachable Time to a value between 300,000 and 900,000 ms.
For more information, refer to http://support.microsoft.com/kb/949589.

---

Problem Cause

The default lifespan of ARP cache entries was lowered from 10 minutes in Windows Server 2003 to a random value between 15 and 45 seconds in Vista/W2K8. As a result, the Provisioning Services bootstraps are 20 times more likely to experience a timeout during a Vista/W2K8 boot.

PVS Machines becoming unresponsive after a period of time with excessive vDisk Retries. PVS machines become unregistered. They are in a unresponsive state and do not respond to ICA, RDP, or Console connections.

For more information, refer to http://support.microsoft.com/kb/949589.