to tell you the truth, i dont know what any of what u just said means.. lol
it doesnt show a message, it jsut closes. and idk if it autosaves, but even then, i couldnt open an autosaved project, you see?
I do see, but if you had a few auto-saves in your maps-folder we would know if your SDK can save maps at all. So far I don't know what could cause this, which is why I'm trying to gather more info.
Can you please post the content of the file Steam-folder/ steam apps/ common/ killingfloor/ system/ Editor.log? Just open it in notepad and copy its content here or upload the whole file.