I have a user that is using remote desktop through a VPN to connect to a remote computer. They have a USB Barcode Scanner device that connects through an emulated serial Com port that needs to go with the connection to use with their POS system. The client PC was previously a Windows XP computer and we had no problems with this forwarding. However, the XP computer has been replaced with a computer running windows 8.1 Pro with Media Center, and now the ports will not forward. I have checked the local resources in the remote desktop connection and ports are set to forward with the connection. Both computers are on a work group, there is not a domain on this network. The server is Server 2008 R2 and is running terminal services (other XP and Windows 7 computers on the VPN are able to forward without difficulty.)
I have also checked in the remote desktop session host configuration, com ports are not disabled in the RDP-TCP connection, and the Remote App manager does not appear to have the ability to control port forwarding that I can find, though it can control other local resources.
Any guidance on this you can offer is helpful, but web searches are only coming up with situations where someone wants to control how ports forward, I was unable to find any information about them refusing to forward.