See: http://msdn.microsoft.com/en-us/library/aa365247%28VS.85%29.aspx

I tried first with your exact path and it caused no issues on
my Win7 box. FWIW you could easily roll your own os.walk
(starting by copying the code that's there) if you needed
to roll in special-cases.

Could you provide a batch file / Python script which exactly
reproduces the issue and a cut-and-paste of the resulting
traceback. (Unless "crash" really does mean "crash").

Would you be able to narrow the issue down any further: see
if any other paths cause the same issue, or if a longer or
a shorter version of the path is problematic.

TJG