Mountain Lion disconnect from Ethernet in sleep mode

I have a late 2009 iMac running Mountain Lion. I use a program called LogMeIn to remotely access my iPhone from other computers and my iPhone. This app worked in Lion, since it was able to work even if my iMac was in sleep mode. However, in Mountain Lion, my iMac looses connection to both my Ethernet and Wi-Fi when it is in sleep mode, renedering LogMeIn useless. In order to use it, I had to sett sleep to never in the Energy Saver prefrences.


So basically, all networking stops on sleep, on both Ethernet and Wi-Fi. I did not encounter this problem in Lion, but ever since upgrading to Mountain Lion it's been happening. Does anyone have any suggestions to fix this? Is anyone else havin

iPhone 4S, iOS 5.1.1, Verizon, 16 GB, Black

Posted on Jul 30, 2012 4:07 AM

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234 replies

Nov 27, 2012 12:32 PM in response to Eric Root

Let me be specific with the issue that I am trying to address. I hope I am in the right forum.

We connect to a server network that is using Windows 2008 R2 with Veritas Cluster Server and a standalone DFS namespace. It is connected by 10GigE networking.


Ever since upgrading to Mountain Lion, the network connection is lost every time the computer goes to sleep. It doesn't lose internet connection, just server network connection. If the computer is running an application that is using a file from the server (e.g., xcel, indesign, word, etc...), that application will crash and the server connection is lost. One of the big reasons for upgrading was to be able to access the DFS network vs. using something like parallels.


Sometimes it's easy to reconnect and sometimes not. Sometimes trying to reconnect may put the computer into a total tailspin and causing the user to restart.


This is very, very frustrating.

Nov 27, 2012 6:06 PM in response to yevinmawson44

I'm having a very similar issue. I have a few smb volumes being mounted on my Mac mini that are on a Windows 2008 R2 server. I upgraded to Mountain Lion last weekend, and now whenever the Mac mini wakes up from sleep mode these volumes appear to be bad. The volumes still appear to be mounted, but when you try and use them in finder no files or directories are visible. I have an application that attempts to read data from these volumes that basically hangs because of this. A reboot is required to re-connect to the volumes. This problem started with Mountain Lion and did not exist in Lion, Snow Leopord, or Leopord.

Dec 1, 2012 4:55 AM in response to loïcfernandezcastrillon

I may have found a solution, well I hope it will work...


I've noticed a difference between my MacBook Pro and my iMac. My MacBook Pro doesn't have the issue of disconnections while asleep.


In system preferences - network, I've noticed that my MacBook Pro has Wi-Fi, Ethernet and FireWire. My iMac has the same, plus PAN Bluetooth which was orange.


I simply deleted the PAN Bluetooth on my iMac to match with my MacBook Pro's preferences.


So far so good, the iMac appears connected all the time even while asleep for a while. I did that before sleep yesterday, I'll live it until tonight (24 hours) and I'll check if I can wake it up.


I'll let you know.

Dec 1, 2012 7:56 AM in response to loïcfernandezcastrillon

loïcfernandezcastrillon wrote:


I may have found a solution, well I hope it will work...


I've noticed a difference between my MacBook Pro and my iMac. My MacBook Pro doesn't have the issue of disconnections while asleep.


In system preferences - network, I've noticed that my MacBook Pro has Wi-Fi, Ethernet and FireWire. My iMac has the same, plus PAN Bluetooth which was orange.


I simply deleted the PAN Bluetooth on my iMac to match with my MacBook Pro's preferences.


So far so good, the iMac appears connected all the time even while asleep for a while. I did that before sleep yesterday, I'll live it until tonight (24 hours) and I'll check if I can wake it up.


I'll let you know.

I suspect that, like many other "solutions", this one is a random conjunction of (a) your taking a certain action, and (b) the Ethernent connection loss after wake-from-sleep disappearing -- for a while.


I've tried all kinds of things others have suggested, and sometimes they have "fixed" it for a day, sometimes even for a week or more -- and yet the problem would recur. The only thing I've found that is a reliable work-around -- but not a permanent cure -- is to execute (with sudo) the Terminal command sequence:


ifconfig en0 down

sleep 10

ifconfig en0 up

Dec 3, 2012 9:46 AM in response to loïcfernandezcastrillon

my iMac is also on WiFi and that goes down at every sleep period: so,it is impossible to download large files without loosing connection.

Apple do something about it please...😢


I've lost count of the number of days that I have been waiting for a solution: none of the tricks on this forum worked so far!!

Thanks to all of you for keeping it going: we can have a party once a solution is available!!!😉

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Mountain Lion disconnect from Ethernet in sleep mode

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