If I understand the problem correctly, there is very simple solution. In order Fiddler to not capture traffic from the local machine you just need to change the proxy settings to not point to Fiddler. This can be easily done by pressing "Capturing" in the bottom left corner of Fiddler or by pressing F12.
However, you will have to do this every time you restart Fiddler. You can make this the default behavior by going to Tools -> Options -> Connections and uncheck "Act as system proxy on startup".
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