fiddler2 unable to generate certificate

Question

I'm using Fiddler2 (or trying) to capture SSL traffic for a windows desktop gadget hitting an https web service. It used to work, and then it stopped a couple days ago, always with this error:

---------------------------  Unable to Generate Certificate  ---------------------------  Creation of the interception certificate failed.  makecert.exe returned -1.  Results from C:\Program Files\Fiddler2\MakeCert.exe -ss my -n  "CN=DO_NOT_TRUST_FiddlerRoot, O=DO_NOT_TRUST, OU=Created by  http://www.fiddler2.com" -eku 1.3.6.1.5.5.7.3.1 -r -cy authority -a  sha1  Error: Can't create the key of the subject ('JoeSoft')  Failed  -------------------------------------------  

(I swiped the error from the google group for fiddler, although I just posted my own and it should be visible soon).

Has anyone else had this problem and solved it? Is Fiddler just broken?

Answer 1

In Win7

• So go here: C:\Users\<username>\AppData\Roaming\Microsoft\Crypto\RSA\
• Select all the files (named with UUIDS).
• Move those files to your Desktop or other folder outside AppData dir.
• Launch Fiddler, go to Tools | Fiddler Options | Enable HTTPS decryption
• See that it works this time (hopefully).
• Move the files back from their temp location (i.e., Desktop),
  to their original one: C:\Users\<username>\AppData\Roaming\Microsoft\Crypto\RSA\
• When one of the files asks whether you want to replace the existing one, skip it.