Comment 3 for bug 572201

Ah, okay, so an OSError is considered the user's fault, and reported differently to other kinds of exception? If the right fix is just treating this error as not-internal, I can do that.

In a sense this is an upstream bug as pywin32 should throw WindowsError from win32 functions like ctypes, or at least their exception type should be derived from WindowsError rather than plain Exception.