I have a Python Windows GUI application (using PySide) that uses multiprocessing.

When I freeze the application I get error messages, in particular that mulitprocessing cannot call flush on a null object.

ISTM That in a Windows GUI application, sys.stdout and sys.stderr may well be None since there is no attached console.

So, I added guards to accesses to sys.stdout and sys.stderr and the problems went away.

I'm not used to creating patch diffs but hopefully the attached (with just a few lines of changes) will be easy to understand.