Ethernet Connection Suddenly gone

Question

Level 1

12 points

Ethernet Connection Suddenly gone

Hope somebody can help.

My iMac has suddenly lost the ethernet connection to the internet. I think the home network is ok because it will only print to my printer if the ethernet cable is connected. I can access the internet via WiFi but not via ethernet. My ethernet port has a self assigned IP.

iMac (Late 2012) running OS X 10.10.5, 2.9 GHz Intel Core 5, 8GB 1600 MHz DDR3, 1TB fusion drive with Bootcamp Windows 8.1 (recently updated which is when connection was noticed to be lost).

I am with BT and have a home hub 4 on infinity 1. I have reset the infinity modem and the home hub all to no avail.

I don't know enough about networks to sort IP addresses etc myself. I've tried the network assistant but again I'm not really sure what to do.

Thanks,

Tim

iMac (27-inch, Late 2012), OS X Yosemite (10.10)

Posted on Sep 10, 2015 2:29 PM

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Answer 1

Sep 10, 2015 3:16 PM in response to TJW69

Try the basics first:

System Preferences>Network

Click the Assist Me button.

In the next window that pops up, click the Diagnostic button & do the necessary. In your case highlight/select Ethernet.

Report back the results as well as the color of the dot.

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Ethernet troubleshooting

Trash the following plist files by going to MacintoshHD>Library>Preferences>SystemConfiguration

com.apple.airport.preferences

preferences

NetworkInterfaces

Restart the computer. If the ethernet starts working, empty the trash. If not, put the plist files back if they have not been recreated. If recreated, empty the trash.

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iMac (Late 2012) running OS X 10.10.5

Conflicting info: You profile is showing "OS X Yosemite (10.10)"

Please update/correct your profile so that you can receive the correct troubleshooting suggestions. This will assist the users in trying to help you. Thank you.

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Answer 2

TJW69 Author

Level 1

12 points

Sep 11, 2015 10:27 AM in response to Baby-Boomer-USofA

Hi I've run the network diagnostics. The ethernet connection in the network window has a yellow dot with Self-Assigned IP underneath it.

The network diagnostics window shows ethernet with a green dot, network settings with a yellow dot then red dots for ISP, Internet and Server. The DCHP connection option then asks me to restart the modem and then the router. I have done this but the network diagnostics is stuck in a loop asking for the router to be restarted. Not sure where to go with this.

I will try the ethernet troubleshooting step later.

Thanks

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Answer 3

TJW69 Author

Level 1

12 points

Sep 11, 2015 10:37 AM in response to TJW69

I've just tried the ethernet troubleshooting steps but that hasn't worked either.

The files that were put in the trash have been recreated but no joy with the ethernet connection.

Any more ideas, please?

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Answer 4

Sep 11, 2015 12:49 PM in response to TJW69

Sorry I am fresh out of ideas except for the following KB Articles for you to try:

OS X Yosemite: If the Ethernet device connected to your computer isn’t working

Resetting the SMU

SMC Reset

Shut down the computer.
Unplug the computer’s power cord and disconnect peripherals.
Press and hold the power button for 5 seconds.
Release the power button.
Attach the computers power cable.
Press the power button to turn on the computer.

OS X Yosemite: Reset your computer’s PRAM

If your Mac doesn’t seem to be remembering your speaker volume, display resolution, or the disk it should be using during startup, you may need to reset your computer’s PRAM.

Resetting PRAM may change some system settings and preferences. Use System Preferences to restore your settings.

Important: To print these instructions, click the Share button

in the Help window, then choose Print.

Choose Apple menu > Shut Down.
Locate the following keys on the keyboard: Option, Command (⌘), P, and R. You will need to hold these keys down simultaneously in step 4.
Turn on your Mac.
Immediately press and hold the Option-Command-P-R keys. You must press this key combination before the gray screen appears.
Continue holding the keys down until your Mac restarts, and you hear the startup sound for the second time.
Release the keys.

After resetting your computer’s PRAM, you may need to update your speaker volume, display resolution, and startup disk preferences. For more information about PRAM, see the Apple Support article About NVRAM and PRAM.

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If none of the above work and/or another user more knowledgeable than I am does not chime in here, suggest that you take your iMac to your local Apple Store or an AASP. Diagnostic testing is FREE!

If you have AppleCare, let them deal w/it. Call them.

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