First, thank you
. I'm actually headed out on vacation tomorrow and if I didn't get your bug report today, I'd've been in big trouble.
The problem you're reporting was indeed very recently introduced, and it only occurs on machines that have never run Fiddler before (or for which the registry settings had been obliterated).
I've fixed the problem in build 188.8.131.52/184.108.40.206, which you can find at http://getfiddler.com/
With regard to your Fiddler2/Fiddler4 discrepancy-- this is expected. The only real difference between v2 and v4 is the version of the framework targeted; for historical reasons, "Fiddler2" is the value that you'll see in registry keys and file paths.
Thanks again, and sorry for the inconvenience!
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