OSX 10.6.8 upgrade disactivated my ethernet port.

Hi all.

I can get my ethenet port to work for a day or so using the safe boot method, then if I shut down and restart, it's lost again.

Has anyone discovered a permanent solution to use?

Thanks,

John

Try OS X Lion. It has been a week since I upgraded to Lion, and the ethernet is working perfectly, the problem seems to be gone.

I'd love to, but my business software isn't compatible (yet). Otherwise I would, and I suspect that's what's happened to a lot of people on this discussion too.

John

I wouldn't mind trying Lion, but the ethernet shouldn't be enabled/disabled on 10.6.8 based on whether or not I upgrade to the next version.

For some of us, a similar issue started with the 10.6.6 update. My Ethernet doesn't say it is missing, though... it just randomly decides to disconnect from the network and then self assign itself an IP address.

For a while, unplugging the Ethernet and just using the WiFi seemed to fix it, but now the AirPort is also self assigning itself an IP address, randomly. Trying to renew the DHCP lease from the router is iffy, as sometimes it works, sometimes it doesn't. When it doesn't, restarting the iMac will allow both network ports to work. But then I have to wonder if I will go days or mere minutes before it starts acting up again.

http://youtu.be/dhncotyiqS0 shows what my network preferences looks like under 10.6.8 when the problem occurs.

This is definitely an OS X problem, and not anything we have done (besides upgrading to 10.6.6 or beyond). Unfortunately, Apple seems very tight lipped about it, since it seems to be intermittant and random as to who it affects.

Sorry, no solution in this post. Only more information which might give someone a clou. Since a few days I've got exactly the same problem on my iMac i7 BUT........running Windows 7 Ultimate 64bit with bootcamp. Setting up a wireless network connection is no problem at all and when I boot with Lion the ethernet cable works fine.

I tried to see which mac adress is used in windows 7 but my computer skills are not greatly developed. I used ifconfig /all but it dit not show an mac adress. I've not tried the boot-in-safemode-solution but will make a new post if that changes the situation.

Thought I'd fixed the problem with safe-mode. But after the iMac was switched off for one day, the problem comes again.

The safe mode lasts only for one start. So I have to go in sleep-mode, otherwise the ethernet is gone again during next start up.

My iMac worked fine (for the day or so that it lived in 10.6.8) UNTIL I upgraded to 10.7.0 Lion.

As my workplace has a strongly locked down LAN, my iMac had full ethernet connectivity, indeed I was able to download the 3.x GB Lion image onto my iMac, and once I started the install it downloaded a further 650MB for the emergency partition. BUT as soon as the machine came up in Lion the Cisco switch port security killed my 'ethernet permit'. This took a week to resolve as even our thread here didn't address my problem (worked OK in 10.6.8)

The IT experts in my corporate LAN have 'solved' my issue by programming the Cisco switch to allow my iMac7,1 to report TWO MAC addresses>>> the one that terminal/ifconfig reveals is 00:1c:b5:xx:xx:xx and the other MAC address that my iMac chooses when it feels like which is 00.00.04.00.00.

That's not such a great approach to security, especially when colleagues come back from holiday and find their Macs potentially reporting the same MAC address?

in summary; it's not just 10.6.8

it does happen to iMacs

it's somehow related to getting things ready for Lion

other have estimated it affects 0.4% of their installed base of Apple computers

FAKE self assigned Ethernet MAC addresses have been seen

The diagnosis reports the 'correct' MAC address when the TCP/IP packets actually have something else

it might be something to do with a new ethernet hardware driver deleting the NVRAM (non volatile ram) of the ethernet NIC (network interface card), in essence bits of the NVRAM becoming 'volatile'.

sometimes a safe mode reboot can improve matters,

sleep mode may be better than 'off' when the NIC can again become volatile

on some Apples nothing has yet restored the ethernet port

a USB to ethernet NIC adapter may offer connectivity

I'm sure some more findings can be added/edited to get through the cloud of problems to point to perhaps a single line of bad ethernet driver somewhere??

I have the same problem on a month old iMac 27" - upgraded to Lion and still the Ethernet port is not work. Come on Apple you need to fix this ASAP please.

I contacted an Apple Engineer on my issue with 'fake' Ethernet MAC address of 00:00:04:00:00 of my iMac with Lion and he has 9th August suggested this course of action:

Thank you for contacting Apple

In regards to the issue noted in your email, please contact your local AppleCare support and reference case #235464101 for what can be done

Hi David,

What kind if response did you get about this? Is there any fix for 10.6.8?

thanks,

Bryce

Hi all,

In my case, before combo upgrade Ethernet works and I can see under H/W system profiler that ethernet is there etc..However, as soon as I upgrade to 10.6.8 it no longer show there and ethernet dies.

Tried all sort of suggested solutions including saving a working networkinterfaces.plist and overwritting post 10.6.8 one....all what thsi did was to re list ethernet which persist in showing as not connected.

hoped an upgarde to Lion solves this, it does not in my case.

has anyone found a solid fix ?

TIA

Sam

Hi.

I'm still having this problem on my MacBook Pro. Update to 10.6.8 and ethernet not even listed anymore. I tried all sorts of fixes, and it had been back for a few weeks. My secretary rebooted the laptop, and boom - ethernet gone again. Apple say the only option is to return it to them, but I can't do without it for business. Wish Apple would look at it!

I was having the problem again a few weeks ago, and discovered that restart the computer didn't solve the problem. Instead, turning it off and then turning it on has worked well, every time I had the problem this was the solution.

This happened a few times to me, then never hapened again.

I went and bought an inexpensive USB hub/ethernet by Kingston. It works and I have a few extra USB ports. I wish Apple would at least acknowledge something isn't right.