I'm torn between feeling that Microbrush program is intuitive and immersive, but also really awkward.
What I have done is create a folder and named it "dxsupport.cgf" thats in "\Steam\steamapps\user\sourcesdk\bin\orangebox\bin" seemed to fix it for me
Update: Guys at Valve have narrowed it down to a new import process for getting items in the game. No ETA. They are working on it now.
Seems to be fixed for me too, though I'm getting this on startup:
Doesn't seem to affect much.
awesome news! Too bad the only mapping I'll be doing tonight is on the face of a pumpkin. The only time its okay to use the carve tool...