Changing the name of a port group when virtual machines are already connected to that port group causes an invalid network configuration for the virtual machines that are configured to connect to that port group.

The connection from virtual network adapters to port groups is made by name, and the name is the identifier that is stored in the virtual machine configuration. Changing the name of a port group does not cause a mass reconfiguration of all the virtual machines connected to that port group. Virtual machines that are already powered on continue to function until they are powered off, because their connections to the network are already established.

Avoid renaming networks after they are in use. After you rename a port group, you must reconfigure each associated virtual machine by using the service console to reflect the new port group name.