I'm having the same problem since the last windows update.  Some change to how the desktop is determined active.  Now, unless I leave a program open on the desktop on my computer, I get a black screen when I VNC into it.  Also, the computer will no longer put the monitor in power saving mode if there isn't a program open on the desktop.  So, I now a the chrome browser open in the corner of my desktop.  If I accidently close it, I cannot VNC into my computer and the screen stays on.  Also, the entire screen now goes black for a couple seconds before it puts up a warning box asking permission to run a program.  This makes multicam stop recording.  I switched back to using the old screen capture that came with PS18.  It doesn't seem to bother it, but it only creates wmv files which I have to handbrake to mp4.

It gets even stranger.  If I use DVI(Dual link) cable between the monitor and computer, it still works fine like it used to.   If I use a display port cable, it doesn't work properly.  Are you using display port?