I have a somewhat unique setup of a GA-Z68X-UD3H that's onboard LAN is not working, so I only have a wireless connection (TP Link WDN4800). I don't have a LAN drop where my hackintosh is located anyhow, so this is fine. iMessage/App Store/iCloud/FaceTime would never connect with this as the sole device showing in system preferences/network, despite following this tutorial and advice of many of the threads above. I added a compatible RTL8169 Ethernet card and still no luck, even with it being hard-wire LAN connected to the router. What eventually worked was a variation of this tutorial thread as follows:
1- Go to System Preferences, and then Network. Remove all network adapters (including firewire).
2- Delete /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist and reboot computer.
3- Go to System Preferences, and then Network. Click on + button, select “Ethernet” from “Interface” combo box, then click OK.
4- Reboot computer again.
5- Go to System Preferences, and then Network. Click on + button, select “WiFi” from “Interface” combo box, then click OK.
My main Apple account I tried failed login to iMessage (the accnt showing both my phone number and email address), but an alternate accnt I used DID make connection to iMessage/App Store/iCloud/FaceTime...crazy right? I signed out of that accnt and tried signing into my main accnt with only the phone # checked (not the email address) and SUCCESS!...It worked...connected to Message/App Store/iCloud/FaceTime. This situation may help one out of a million iMessage troubleshooters, but I hope it may shed some light on a potential fix.