Like many new laptops, the new Apple MacBooks are too thin to have an onboard Ethernet adapter. After setting up a local account and connecting it to the internal wireless network (using WPA2 Enterprise), I was able to join the Macbook to the Active Directory domain without issues. However I quickly discovered that I couldn’t login to a domain account because by default wireless connections are not connected before login – remember, no Ethernet.
 
The immediate “fix” was to purchase a USB3 gigabit Ethernet adapter, but after some research later I discovered it's possible to enable WiFi before login. Here are the basic steps:

  • Install the Apple Configurator utility from the App Store. This app is designed to create deployment profiles for iOS devices but can also be used to create 802.1x profiles for OS X systems.
  • Run the Configurator and create a new profile. Update the WiFi section with the required connection information.
  • Save this profile locally.
  • Open the profile with a text editor and add XML text as outlined at http://www.ntsystems.it/post/Joining-WiFi-before-login-on-Mac-OS-X-108.aspx. This article is for an older version of OS X and refers to the discontinued iPhone Configuration Utility (which was replaced by the Apple Configurator), but the manual edits still apply to OS X 10.10 and 10.11.
  • Double-Click the edited profile to import into System Preferences. You can see the loaded profile by going to the 802.1x section of the Network->Advanced settings in System Preferences.
  • Logoff or reboot and you should be good to go.