Client side certification failure in non-proxy mode after installing and using Fiddler.

[Jim]

Hi All, I hope someone can help!

On a Windows 10 machine, I installed and ran the latest Fiddler version (v4.6.3.44034) and was able to successfully capture and decrypt HTTPS sessions using the proxy server.

Now, I am trying to return to normal operations, running without the proxy server.  One of the sites requires a client side certificate be attached to the request and this request now fails with error -2146233079 (The request was aborted: Could not create SSL/TLS secure channel).

This was working just fine prior to the Fiddler install, under the current user, not the admin account.  Fiddler was also installed under the same current user.

If I run the application as Administrator, it works.  So, how do I undo whatever permissions change that was made by Fiddler which prevents me from accessing the client side certificate that I had no problem accessing before?

I have tried the following so far:

1) Fiddler Options > HTTPS > Remove Interception Certificates

2) Fiddler Options > HTTPS > Rest All Certificates

3) Uninstalling Fiddler entirely

Thank you!

[Tsviatko Yovtchev]

Hello,

Fiddler doesn't really do permission changes. Is the client certificate in your user store?

Regards,
Tsviatko Yovtchev
Telerik by Progress

[Jim]

Hi, thanks for the reply.

The certificate is in the Trusted Root store.  Pre-Fiddler I could access that certificate without any trouble.  Post-Fiddler, I now have to run my application with elevated privileges ("as administrator").   Fiddler may not directly, um, fiddle with permissions but unfortunately something was inadvertently changed.

Thanks again for any thoughts or advice you may have,

Jim.