How to crash CPython 3.1.1 in Windows XP: python -c "import os; os.spawnl( os.P_WAIT, 'blah' )" I reported this as a bug, <url: http://bugs.python.org/issue8036> Workaround: it seems that spawnl is happy with an absolute path as second arg, followed by a third arg which should be the name of the program (repeated). Cheers, - Alf