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httpsfiddlermakecert

fiddler2 unable to generate certificate

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 
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(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?

Solution

  • 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.