When opening anywhere between 5 and 9 remote sessions in Remote Desktop Connection Manager, opening another session gives an error with a code of 3334. I was remoting from a Windows 7 machine to Windows Server 2012. I don't experience the issue while remoting into Windows Server 2008 machines.
This fixed it for me:
- On the system where you run RDCMan, Run "dcomcnfg.exe"
- Expand Component Services, My Computer, Distributed Transaction Coordinator.
- Right click on "Local DTC" and select properties.
- Click the "Security" tab
- Check the "Network DTC Access" box.
- Under "Transaction Manager Communication", select the "No Authentication Required" radio button.
Source: This Microsoft forum.
Update: This fix only worked for me for a short time, then the same errors kept popping up. I am now hearing rumors that there is just a bug in the RDCM and Microsoft has yet to release the new version. Apparently, there IS a new version that we have spied Microsoft employees using, though. I guess we just wait...