Clear Automatic Proxy Configuration box in MBP Network settings (El Capitan) So I input the URL for my school's proxy server in the automatic proxy server box in network settings (under advanced and then proxies). I want to now clear this box (yes, I realize I can uptick the box to turn off the proxy server). However, if I delete the URL, click OK, then press Apply, when I go back into the proxy server settings the url is still there.

Does anyone know how to clear the field so it stays cleared (I also realize I can replace it with 0000000 or something nonsensical, but I prefer to have it cleared).

Admittedly, I have not tried a computer restart (and pram reset), which is dumb on my part, so I will try that now. If I don't edit this post saying that cleared the box,though, then it did not work.
I just ended up going to the preferences.plist file and manually changing the settings, which worked.

Note that I had to disable csrutil (system integrity protection). I'm not sure if that is new to El Capitan or not.

Edit: Sorry for edit, just want to say that that seemed to mess up some stuff (for example it would connect me to a network but say I was not connected). I'm not sure how I messed up... but I just went with replacing the preferences.plist with a time-machine backup of it. I should have just don't that in the first place.