Troubleshooting macOS Trust Certificate Issues


Product Version 1.0.0 and above
Supported OS macOS
OS tool Keychain Access


To capture secure (HTTPS) traffic on macOS, Fiddler Everywhere requires the installation of a root trust certificate in the macOS Keychain Access application. This process failed and I'd like to know how can I handle the "Fiddler root certificate NOT trusted successfully" error?


Test the import of the Fiddler Everywhere root certificate on macOS by using custom bash scripts and terminal commands.

  1. Create a Bash file, for example,

  2. Save the following script in

    login_keychains_paths=$(security list-keychains | grep -e "\Wlogin.keychain\W");
    if [ -z "$login_keychains_paths" ]
            echo "No login keychain found.";
            exit 10;
    security add-trusted-cert -k login.keychain ~/Desktop/FiddlerRootCertificate.crt;
    if [ $security_exit_code -ne 0 ]
            echo "security add-trusted-cert failed with error code $security_exit_code";
  3. Make the file executable.

    chmod +x
  4. Execute the created file in your Bash shell.

  5. After successfully executing the file, you will be prompted for your macOS username and password. Enter the credentials, and the generated trust certificate will be added in the Keychain Access application in login > Certificates as DO_NOT_TRUST_FiddlerRoot.

  6. Test that the certificate generated from Fiddler is successfully installed and trusted by running the following command in your Bash shell:

    security trust-settings-export /tmp/trustSettings.xml

    As a result, the command outputs a success message:

    ...Trust Settings exported successfully.
  7. Go to login > Certificates and confirm that the DO_NOT_TRUST_FiddlerRoot is present in the Keychain Access application. Double-click the certificate, scroll to the bottom and note the SHA-1 value. Open the exported settings file from /tmp/trustSettings.xml and check that the SHA-1 value is present there. For example, the certificate from your Keychain Access application will be identical to the SHA-1.

    The SHA-1 key in the trustSettings.xml file will also be present in the Keychain Access application.


    Check SHA1 signature

  8. (Optional) Delete the /tmp/trustSettings.xml file after troubleshooting the issue as it is only needed to check that the SHA-1 key is properly exported.