Message 65201 - Python tracker
So let's it interpret this way: range(1, 300000000) consumes more and more memory, and causes the system to hang. When python.exe is in a console, you have the ability to close the window and kill the process. When using Idle, the interpreter cannot be killed so easily: I suppose you closed the main windows, but this did not kill the subprocess used to run commands. BTW1: did you try xrange(1, 30000000) BTW2: msg65177 is not a pseudo... it's the message ID in the bug tracker ;-)