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Level 1

13 points

iMac loosing wired Internet connection after going to sleep

Since this weekend my iMac (27", Core i7, Mac OS X 10.8.2) loses its Internet access after going to sleep (it's connected to a router by Ethernet cable and has been working mostly trouble free for more than 2 years now; Network preferences pane is configured with a fixed IP for the Mac and the standard adress of the router).

If I connect my Macbook to the same cable the connection to the Internet works just fine.

All internal connections always work (between my Macs, PS3, printer etc.).

Temporarily switching on AirPort and clicking a few links, then switching wireless off again, restores Internet access for the wired connection until next sleep.

I didn't install any new software or hardware recently, nor did I change any network configuration.

This happens repeatedly. Anybody have an idea to what's going on here?

OS X Mountain Lion, 8 GB RAM / 2 TB HD

Posted on Oct 2, 2012 12:22 AM

18 replies

Dec 5, 2012 10:52 AM in response to sweetcaro

I was happy for about a month without the issue since I switched to Mountain Lion and the issue just started happening again

not sure if an update chagned something

now I lose internet every 10 minutes

very frustrating, apple needs to get this fixed

rvjacobs

Level 1

19 points

Feb 4, 2013 11:31 AM in response to Charel

Hello you all,

I also had the problem of a disconnecting wifi while my imac was sleeping. I did not have the reconnecting issue after sleep, but the lost connection issue during sleep which made it impossible to reach my imac for things like homesharing, apple tv or remote desktop. I have a late 2012 iMac with a clean ML 10.8.2 on it and wirelessly connected to an apple time capsule (same as an airport extreme). My partner has a mid 2007 iMac, also with an ML 10.8.2 on it.

I tried every single solution I could find on the internet, such as changing the router's security from wpa2 to wpa, changing the MTU from automatic to manual 1453, router reboots, re-installations, re-configurations, keychain clean-ups, everything.

Eventually I solved my problem with these steps and now it works as a charm. I can still find the iMac with the remote app, even after 12 hours of sleep:

My time capsule router is set on automatic MTU and encrypted with WPA2 and I use the 5Ghz network!

1. Cleaned all the wifi passwords in keychain on my iMac

2. Created a new network location in system preferences

3. In this location I deleted the bluetooth pan and bluetooth dun connection.

4. In this location I changed the preferred connection-order to wifi on #1 and ethernet on #2.

5. Restarted my iMac.

Now I still have a connection when it sleeps and I can wake it to low profile using the remote app (homesharing) and everything works fine.

Hope more people wille be helped by this.

May 28, 2016 8:07 AM in response to sweetcaro

I've experienced this issue for several months. Finally spent a couple hours on the phone with Apple support. We were able to isolate the problem as the Norton suite that came free with Comcast internet. Shutting it down eliminated the problem. Norton removed, wired internet connection happy.

iMac loosing wired Internet connection after going to sleep