obfs4proxy causes issues on Windows with certain AV products.
From the Tor Browser 4.5-alpha1 post:
my system was crashed and shut down when i Run obfs4 transport!!! also my antivirus acted (Bitdefender)
win 7/ultimate 32 bit
I don't have BitDefender, and I verified that obfs4proxy works on:
- Windows 7 Professional (32 bit)
- Windows 8.1 (64 bit)
As other people also report that it works fine, for now I assume this is a weird AV false positive/interaction, but further research is needed.