Often, especially in virtual machines, when you try to rename a network adapter you get the message “Cannot rename this connection. A connection with the name you specified already exists. Specify a different name”.
This message indicates that there is a record for a network adapter that you cannot see in the “Network Manager”. To see the records you need to start the “Device Manager”. I find the easiest way to open device manager is to open a PowerShell or Command screen and type DEVMGMT.msc
Once Device Manager is open, expand network adapters, and select ‘show hidden devices’ form the ‘view’ menu item.
Unused devices can then be uninstalled.