Network Preferences Not Responding

Ever since upgrading to El Capitan I've been unable to access my network preference pane. System Preferences launches normally via the Apple menu, dock, changing the wallpaper, etc - every pane is operational except network. Whether clicking the network pane in System Preferences or going to the WiFi menu bar icon > Open Network Preferences, it simply says 'No services in this location' (it's set to Automatic). It doesn't show my current WiFi network or Ethernet access.

Clicking on anything while this pane is open, including going back to the System Preferences main menu, causes SysPref to stop responding and give me the rainbow wheel. From that point all I can do is force quit.

Network preferences are probably the ones I use most so this is an enormous hassle and Apple hasn't gotten back to me about a fix (I've been sending error reports about it for weeks - since El Capitan was in beta). I excepted it to be fixed in the final release.

I wiped the drive and performed a clean install from USB; no dice.

I erased systemprefs.plist; no dice.

Any suggestions? I'm running out of ideas especially since wiping & reinstalling El Capitan didn't fix it. Any input would be appreciated 🙂