Can’t access local resources when VPN connected (Vista & Win7)

Windows Vista introduced a new feature that allows PPTP VPN credentials to access resources on remote servers when the VPN is connected. The side effect is that access to local resources then fails.  The feature can be disabled per VPN as follows:

Locate the .pbk file that contains the entry that you dial:

%AppData%\Microsoft\Network\Connections\Pbk

Open the file in Notepad.  Locate and change the setting for each VPN: UseRasCredentials=0