Npalamidis
Level 1 (17 points)

Q: 27"iMac (mid 2011) wifi won't wake up from sleep

I have been using my brand new core i7 27" iMac for the last week! And I have noticed a wifi bug that's driving me crazy!

 

Everytime my iMac goes to sleep when I wake it up the wifi won't detect any networks at all. It's just like if the wireless card is still sleeping! At first I waited for a while because I thought it would take longer to wake up! But it never detected any networks at all.

 

If I manually turn the wifi Off and then turn it back ON then  it detects my network and all the wireless networks around with any problem.

 

My home router is an Airport Extreme Dual Band !

 

Is anyone out there having the same issue?  or could it be that I got a faulty airport extreme card in my iMac??

iMac, Mac OS X (10.6.7)

Posted on May 12, 2011 8:48 PM

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Npalamidis

Q: 27"iMac (mid 2011) wifi won't wake up from sleep

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  • by fullstop,

    fullstop fullstop May 27, 2011 10:53 AM in response to Npalamidis
    Level 1 (20 points)
    May 27, 2011 10:53 AM in response to Npalamidis

    Can you pastebin (www.pastebin.com) the output of "sudo dmesg" from a terminal?  It might give some insight into what the wlan card is doing.

  • by Npalamidis,

    Npalamidis Npalamidis May 29, 2011 7:42 PM in response to Npalamidis
    Level 1 (17 points)
    May 29, 2011 7:42 PM in response to Npalamidis

    Last week I got an email from an Apple Engineer, He asked me to run some terminal codes and send some log data to him.

     

    Then he asked me to put my router in channel 36 (5GHZ band).

     

    And Magically this solved the issue!

     

    Now I believe that the problem is that the new iMac's only search on for networks on channel 36 after wake up.

     

    If by any chance your Wifi Network is not on channel 36 then you iMac won't detect it.

     

    At least I have a temporary solution!

     

    Please Try it and  post back if it works for you guys!

  • by Bo Boivie,

    Bo Boivie Bo Boivie May 30, 2011 12:26 PM in response to Npalamidis
    Level 1 (65 points)
    May 30, 2011 12:26 PM in response to Npalamidis

    Same problem for me with my brand new iMac 21"

  • by DamenS,

    DamenS DamenS Jun 20, 2011 8:47 AM in response to Npalamidis
    Level 1 (0 points)
    Jun 20, 2011 8:47 AM in response to Npalamidis

    I am also having the same problem on my Mid 2011 iMac 27inch with i7 processor - if I go to System settings/Network/Assist Me/Network Diagnostics it will initially say my ISP has failed, but then connect again straight away.  Unfortunately this is very inconvenient as I am having to do it at LEAST 10 times per day and there are no problems with the same computer running Windows 7 in Bootcamp (which would suggest that if there are driver issues, they do not affect the Bootcamp Apple-supplied drivers).

  • by scott49,

    scott49 scott49 Jun 20, 2011 10:22 AM in response to Npalamidis
    Level 1 (0 points)
    Jun 20, 2011 10:22 AM in response to Npalamidis

    Same issue, started happening a few weeks ago for 21" iMac(6 months old) with a Belkin wireless router. Get a message that my preferred network isn't available, but then it clearly shows that it is. When I try to join the network it takes several attempts, if it joins at all.  Like the other postings, I know that its not a router issue since every other device I have stays connected. Very irritating indeed...

  • by aqui,

    aqui aqui Jun 21, 2011 7:22 AM in response to Npalamidis
    Level 1 (0 points)
    Jun 21, 2011 7:22 AM in response to Npalamidis

    Hi, I have a different issue although the problem is still the airport. I just bought the 21" i5 about 3 weeks ago and after the computer sleeps, i can't open a page. even though my airport logo is connected. and it can see other networks. i need to turn off and turn on again the airport or renew dhcp before i can connect to the internet. hope they can fix this as soon as possible.

  • by garynfromaustin,

    garynfromaustin garynfromaustin Jul 30, 2011 5:12 PM in response to Npalamidis
    Level 1 (0 points)
    Jul 30, 2011 5:12 PM in response to Npalamidis

    you can try and go to your system preferences.  Choose energy saver.  and Uncheck "wake for network access"  that way when your computer sleeps it does not lose its network connection.  let me know if it works

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