Hey Dotazorro42,

Is Fiddler Everywhere starting successfully and then not capturing any traffic (or, for example, not capturing just HTTPS traffic)? 

The first thing you should do is to check your OS proxy settings for leaked proxy configuration.

- Stop Fiddler Everywhere, capturing and exit the app.

- On Windows 10, open the Proxy Settings windows and verify that the Manual Proxy Configuration is off.

- Start Fiddler Everywhere and enable capturing mode.

- Return to the OS proxy settings windows (close it and reopen it to trigger the change) and verify that the Manual Proxy Configuration is set now active with 127.0.0.1:8866 as Fiddler proxy IP and port.

At that point, by default, you should be able to capture any non-secure traffic (e.g., like http://example.com). If you cannot capture secure traffic (HTTPS), then verify that you have installed and trusted the root certificate (instructions here). You could also check if there are other tools that are modifying the OS proxy and turn them off while using Fiddler.