Internet Sharing Issues (WiFi to Ethernet) For some reason my internet sharing has decided to stop working. It was perfectly fine about a day ago, no issues, no hiccups, but today it differs. It won't work at all. 

I'm connecting my MacBook Pro Early 2011 model (Running 10.8.2) to a Windows computer via ethernet (I'm still waiting for the wireless card to come). It was working without an issue until I unplugged my MacBook Pro while Internet Sharing was on. Now when I connect it again (while IS is on) it will show connectivity on the Mac, but no internet on Windows. Here is what I see when the cable is connected (to both machines) and Internet Sharing is on:



... and the following: 



As you can see the option "Share Your Connection From" is for some strange reason blank, and yes, I have tried countless times to turn it off, click Wifi, and turn it back on. When done so the "WiFi" will only display on the dropdown-list until I close the Internet Sharing option. 

I have also noticed that even when I don't have Internet Sharing on, my MacBook Pro still connects to the ethernet and actually states: "Ethernet is currently active and has the IP address 169.254.16.1."

I would appreciate any help, thank you in advance.
I don't have a definitive answer, but I've got some ideas to start, and perhaps we can narrow it down as you try some things and provide more information.


For starters, check the lock status of the Sharing Preferences. The lock icon in the bottom left corner should be open when you make changes. I've run into some problems where the interface would allow me to make changes, but they wouldn't save because it was locked.

If it is open, set up sharing as you would, then lock it after. See if that makes the configuration stick.
Try removing /Library/Preferences/SystemConfiguration/com.apple.nat.plist (you may want to make a backup copy just in case). Then try re-enabling Internet Sharing (which should regenerate that plist file). It's possible something got corrupted in the configuration file.