Hi,
If you are using Window 7, go to Task Manager and end process all following program:
√ MossAnalysis.exe
√ MossDraw.exe
√ mossglobals.exe
√ MossLauncher.exe
√ MX.exe
√ moss.exe
You may find some of the program not avaiable based on your MXROAD version.
It would be good if you always starts the question with MX version and Operating System (OS).
Different MX Version has different type answers and it always tied with OS as well.
Heading like [MXV8iSS4_081109845_Win8Pro] Unable to exit MX can help to get the answer faster.