I ended up restarting with the Ethernet cable plugged in > In system preferences I setup a manual connection instead of DHCP. The other computers on my home network worked fine and I tried the afore mentioned cable swap, port swap out the router and switch, Reset PRAM, went to church on Sunday, made my bed, etc.

I thought it was a defective cable or switch. Strange part is that the ethernet connection at my office works fine, but not at home. It belongs to my school district and if I send it in I probably won't get it back for about 6 weeks at which time, I'm planning to retire and will have to give it up anyway. Any suggestions? I really don't want to send it in for repair. My old desktop Mac is connecting just fine and the router lights up when I move that cable to different ports so I don't think the router or the cable is the problem. I suspected the cable but I've tried four different ones and different router ports to no avail. (I usually use it on Airport at work but on Ethernet at home.) It continues to show the ethernet cable as being unplugged and the router light will not light up when the cable is in the MacBook. In Sys Pref - Network I turned off the Airport so that it would not look there.

I woke it up and now it won't connect to the internet. I closed the lid on my MacBook and set it aside but left the ethernet cable plugged in. I was on internet yesterday until about 6:00 pm.

Mac ethernet not showing up