I have Windows 8.1 Pro running on my desktop computer and on my notebook. Both are fully patched and updated. I can connect to an SBS 2008 server remotely from the notebook, which has mstsc.exe with a version number of 6.3.9600.16384. I am unable to connect to that server from the desktop, which has mstsc.exe version 6.3.9600.17415 installed.
Both computers have the same URL entries in IE 11 in the Compatibility View and for Trusted Sites. The only thing I noted when I first tried to connect to the SBS 2008 server from the notebook was a popup that said in order to make the connection I had to install something. I was in a hurry so I just clicked through to get the connection established and now I wish I had noted what it was that I installed to make things work from the notebook.
Exhaustive research has not revealed anything useful in trying to resolve this issue on the desktop computer. I have tried to delete mstsc.exe on the desktop computer and replace it with the earlier version from the notebook (after saving a copy of the newer version, of course) to see if that is the problem but Windows is being super protective and not allowing that to happen. An additional complication on the notebook - a Lenovo X1 Carbon Gen 2 - is that the server desktop comes up in a window that is only about 1/4 of my screen size. This makes it difficult to work with that small of a display.
Thanks in advance for any assistance you might have.