My company relies on RDM for supporting all our hosted client terminal server environments. We use a universal printing solution called UniPrint, which relies on a virtual RDP channel for transferring print jobs to a UniPrint client application on local PCs. It establishes the virtual channel via a key under HKEY_CURRENT_USER\Software\Microsoft\Terminal Server Client\Default\AddIns that points to a DLL file. Many third party apps create virtual RDP channels in this manner.
The issue is that when attempting to use RDM on a Windows 8 PC, the UniPrint virtual channel fails. If I use the full mstsc.exe, the virtual channel works fine, but when embedding a session within the RDM window (which means it's using the RDP activex control), the virtual channel fails every time. We are currently using RDM 6.0, and I had no issues with the virtual channel with RDM 6 on Windows 7.
However, before we blame the outdated RDM version, I have also tested RDM 8.0 on Windows 8, and the virtual channel still fails, so it would seem that this is some sort of Windows 8 problem. Again, this problem only exists using embedded (activex) sessions in RDM on Windows 8. Embedded sessions work fine on Windows 7, and external RDP sessions on Windows 8 also work fine.
I'm uncertain if this is a bug in Windows, or if something changed with how the RDP activex control works in Windows 8 that now requires a coding change in RDM. Windows 8 does have a new RDP client that uses the new RDP 8.0 protocol, so I suspect that may be the issue.
The issue is that when attempting to use RDM on a Windows 8 PC, the UniPrint virtual channel fails. If I use the full mstsc.exe, the virtual channel works fine, but when embedding a session within the RDM window (which means it's using the RDP activex control), the virtual channel fails every time. We are currently using RDM 6.0, and I had no issues with the virtual channel with RDM 6 on Windows 7.
However, before we blame the outdated RDM version, I have also tested RDM 8.0 on Windows 8, and the virtual channel still fails, so it would seem that this is some sort of Windows 8 problem. Again, this problem only exists using embedded (activex) sessions in RDM on Windows 8. Embedded sessions work fine on Windows 7, and external RDP sessions on Windows 8 also work fine.
I'm uncertain if this is a bug in Windows, or if something changed with how the RDP activex control works in Windows 8 that now requires a coding change in RDM. Windows 8 does have a new RDP client that uses the new RDP 8.0 protocol, so I suspect that may be the issue.