Problem: No Traffic is captured with ProxySettingsPerUser=0 Group Policy Setting

Your system or domain Administrator has set the Group Policy setting ProxySettingsPerUser to 0. This means that instead of the default Windows behavior (each user has their own proxy settings), instead all user accounts share one set of proxy settings. In this case, a value named ProxySettingsPerUser exists inside:

    HKLM\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ 

Solution: Run Fiddler Classic as Administrator

This machine-wide proxy setting can only be changed by code running as an Adminstrator, so Fiddler Classic must be started Elevated:

1. Right-click the Fiddler icon in the Start menu.
2. Choose Run as Administrator.

This will adjust the proxy setting.

If you cannot run Fiddler Classic as Admin (because, for example, you're not an Administrator) you will need to request that your system or domain administrator disable this policy:

    HKLM\SOFTWARE\Policies\Microsoft\Windows\CurrentVersion\Internet Settings\ProxySettingsPerUser is 0.

This policy setting does not impact clients that are not configured to use the system proxy settings (For example, Firefox with a manual proxy configuration).