Can't enter commands (but can orbit, zoom etc)

I have and recurring problem:
Sometimes the program seem to “freeze” in a strange way; I can still orbit and zoom, turn layers on and off, but I can’t enter commands. This means I can’t work with the model (i.e. make and geometries etc) and a bigger problem is that I can’t save the model, since save is a command.

How do I solve this problem? I need to restart the program without any of my work being lost, or “unlock” this frozen mode.

Hi Konrad - what does the command line show in these cases, anything? Can you please run the SystemInfo command in Rhino and post the results here?

-Pascal