It is bad practice to force shutdown using brute force tactics. Rather, as @Aragon pointed out you should add error handling to your script to isolate components and/or stop the script if certain conditions are not met. As @R.K. points out, the ArcGIS python console is next to worthless for running complex scripts and, in practice, should be reserved for simple operations--stick with [IDLE][1], [pythonwin][2], [pyscripter][3] or any of the host of other IDEs. Here are discussions related to your question: [How do I use sys.exit(0) in an arcpy script to exit early without having an error message show up?][4] [Terminating a Python script][5] [How to stop a command or prompt in Python?][6] [1]: http://docs.python.org/2/library/idle.html [2]: http://sourceforge.net/projects/pywin32/files/pywin32/ [3]: http://code.google.com/p/pyscripter/ [4]: https://gis.stackexchange.com/q/14163/8104 [5]: https://stackoverflow.com/q/73663/1446289 [6]: http://forums.arcgis.com/threads/27208-How-to-stop-a-command-or-prompt-in-Python