mountain lion ethernet not working mac pro 2010

Everything worked... I just installed a fresh version and the download via ethernet worked but as soon installment was completed again the same problem..

Dear all:

mine is early MBP 15'' i7, just upgrade snow leopard to Mountain Lion,

after finishing upgrading, I couldn't use RJ45 to get online but ip configuration are jsut fine,

and I don't have anything between cable modem and MBP, I also couldn't share mini server 's

screen with MBP,after researching all day, and read above ... I tried a way and it worked,

which is delete the original ethernet and create a new one.. and it works as usual now..

just a suggestion, hope it helps

new info:

if i put my iMac to sleep, restart, the ethernet card works, if i stop him again, no longer works.

***UPDATE FROM APPLE SERVER ENTERPRISE LOOKS LIKE THE FIX WILL BE IN 10.8.1***

Greetings Spiro,

"Thank you for calling Apple. I was able to reproduce the issue exactly as you described and submitted an escalation to my Engineering team. I expect to have a response I can pass along in the next couple of days.

I just received a response from my Engineering team. They are working to analyze the cause of the issue. Any change in behavior will likely to be delivered in the form of a Software Update, though I cannot speculate as to when that may occur.
Thank you for letting us know about the issue, and I will keep you up to date as appropriate".

--
Regards,

Jonathan
Apple, Inc.

Finally I found a thread with active people that have the same problem.

I have a mid 2011 iMac 27" at its maximum upgradability, and the issue is as follows:

the ethernet is shown to be unplugged, but spontaneously reconnects on a cycle of about every two hours...2 hrs on , 2 hrs off...

none of the many solutions I have tried and been suggested to work.

I too am waiting for a patch. Hopefully quickly.

Problem as above:

Listed in two other communities

https://discussions.apple.com/thread/1645716?answerId=19033486022#19033486022

https://discussions.apple.com/thread/4140461

I have found a fix for this, at least got my ethernet back up and working.

I suspected from various posts this was due to having an 'unusual' network setup.

By unusual I mean I was using both of the ethernet ports on my Mac Pro, with VLAN interfaces on the second port.

I deleted the network preferences fully ( remove /Library/Preferences/SystemConfiguration/preferences.plist ) , as described here.

http://stevejamesson.com/2008/10/01/reset-mac-os-x-network-configuration-factory -default-airport-interface-disappeared/

A reboot then brought me back up with a working set of ports, I'll now try to re-add the vlans.

Hope that helps and I'll be removing all non Automatic default locations before doing any more upgrades.

NB: I do not know if this removes other settings you may be attached to so caveat emptor.

Message was edited by: Dean M Smith - Added caveat

Try going in to settings>network>ethernet>advanced>click Renew DHCP Lease (under TCP/IP) and then see if it works. It worked for me!!

Sorry buddy but if the solution had been that easy......

it didnt work! but thanks anyway.

So I realized my Mac was under warranty.

I called support and spent and hour with them doing everything I had already done:

Zap Pram, new location, remove and re-enter ethernet setting, new user, reboot in recovery and more.

They sent out a repair guy who swapped out the logic board. It now works.

There is no question everything was working fine just before the 10.8 upgrade. I had a similiar hardware failure (speakers stopped working) years ago on a PowerBook after a software upgrade. That too resulted in a logic board swap under warranty.

Berrisj1, What you write is so completely misleading!

This is the negative aspect of public forums....

....its obviously a driver issue....

anyway!