Fiddler 2 or 4 not working in windows 10

Question

Fiddler 2 or 4 is not working in my windows 10. I cannot capture traffic for any browser. Before upgrade to windows 10 it was working in windows 8. Some body has the sam problem? Any Solution?.

Answer 1

I had a similar issue whereby not HTTPS traffic could be picked up by Fiddler in Windows 10.

Resolved as follows: In Fiddler (v4.6.2): Tools Menu >> Fiddler Options >> HTTPS Tab >> Actions button >> Reset All Certificates.

Apparently the issue (at least the one I was having) was caused by having a mixture of old and new certs:

I’ve made changes to the latest versions of Fiddler to improve the performance of certificate creation, and to avoid problems with new certificate validation logic coming to Chrome and Firefox. The biggest of the Fiddler changes is that CertEnroll is now the default certificate generator on Windows 7 and later. Unfortunately, this change can cause problems for users who have previously trusted the Fiddler root certificate; the browser may show an error message like NET::ERR_CERT_AUTHORITY_INVALID or The certificate was not issued by a trusted certificate authority.

Ref: https://textslashplain.com/2015/10/30/reset-fiddlers-https-certificates/

Answer 2

Check if your browser proxy is set to localhost:8888 when fiddler is running.