MacBook will not recognize ethernet cable

I know this sounds silly, but have you tried restarting with cable plugged in?

For what it's worth, I have two MacBooks - one for me and one for my wife. Both have been trouble free, and the iBook predecessor was nearly as good. Both of the MacBooks are far more reliable for me than the HP laptop & Windows that my employer forces me to use. In my objective experience, the Macs are improving and better than the Windows competition. That said, nothing made by the hand of man is perfect, but before you make the leap to Windows, check carefully into the on-going issues with Vista.

Best wishes!

I have the same problem, but I can't find answer for a week! I have reinstalled mac os, but mac still won't recognize cable.. Does anybody have any ideas?

I've got the same problem. I was connected to ethernet, closed the lid and now all I get is an orange and red light in network preferences. It will light up orange "no ip address" then flash for a second to red then back to orange. I've restarted the laptop and the router and it still does not work.

I know the cable and router are ok because an old powerbook g4 connects fine with it.

Try resetting NVRAM. Restart, then press Option-Command-P-R until you hear two beeps. This did it for me. I can't explain why it worked though...

Let us know if it works. This problem gets a lot of hits on google, but few solutions, and even less explanations.

I've been having the same issue with my MacBook.
Cable Modem>DLINK wired GB g router>DLINK GB Switch>MacBook
When the MacBook goes to sleep/wakes up it will sometimes lose the ip address and I have to restart the MacBook to obtain the ip address via the wired ethernet. Very frustrating....

I've also had this trouble for two days... Strange part is that the ethernet connection at my office works fine, but not at home. I thought it was a defective cable or switch. 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... Nothing worked.

I ended up restarting with the Ethernet cable plugged in > In system preferences I setup a manual connection instead of DHCP. It didn't take at first, but when I ran the "assist me" option, I selected the Built-In Ethernet, went through the process, and it seemed to work. So far, so good...

One interesting note, I have Parallels installed and the Parallels program was able to see the Internet even though the Mac side was not (said the cable was unplugged on the mac side). I have about 15 MacPro's running on my office network and a couple more at home. This has only happened on my MBP 17" (2.16)... Running SonicWall TZ170 on both networks. Weird stuff. This solution got me up and running again. Hope this helps.

It may be as simple as taking the cable out and reinserting. It has happened to me a couple of times. The connection becomes loose.

Are you kidding me? Do you really think that the people in this post have not taken the cable out and reinserted it?

i had a similar problem. claimed ethernet cable was unplugged when it was not. ethernet worked fine under windows with bootcamp. i tried suggestions on this thread and the only thing that worked was using the "assist me" button in network preferences. be sure to choose "ethernet". it instantly woke the ethernet port from the dead.

This is the solution that worked for me as well when my macbook did not recognize my ethernet connection. Choose the "assist me" button in network preferences. I played around with the connections options and then unplugged/replugged the ethernet cord from both ends and then I my connection worked.

I've been having a similar problem - after using wireless at home, I plug in the ethernet cable at work, but it never shows up as being connected in the network preferences. 'Assist me...' didn't help in this case. But I remembered an old trick that I used to use either on linux and on Windows command-line:

(cable is unplugged - don't know if that's req'd, but I don't think so)
sudo ifconfig en0 down
sudo ifconfig en0 up

I plugged in the cable and bingo - connected.

Hi,

I have the same problem and tried all the solutions above.
The hardwaretest gave no result, the driver is loaded, the card is recongized (Systemprofiler, networksetup cmd line tool) finds en0 . . . What else can I try to "reactivate" relink the card?

Alexander