iMAC 21" WIFI failing after 10.7.4 update

Or maybe even better: Submit a bug report here: http://bugreport.apple.com

I just did!

tried but it wouldn't let me. it seems you have to be a registered developer 🙂

tried but not holding my breath!

I had the same problem, and I solved when I removed the my prefered network from network panel and disabled the security (WPA2) from my router (TP-LINK TL-MR3420).

Once conected I returned all security settings, and the wireless connected normal.

The proposed actions do not help with this issue. The WIFI still drops, and the iMac is no longer able to see any wireless networks.

But: I have a feeling that the issue is related to Time Machine. I restarted the iMac, and the wireless network was connected. I opened a web page with success. Then I manually started a Time Machine backup, and the second I did that the wireless connection was gone. This is also seen in the kernel log as follows:

🙂 WAKE UP

May 18 18:45:07 imac kernel[0]: Wake reason: EHC2

May 18 18:45:07 imac kernel[0]: Previous Sleep Cause: 5

May 18 18:45:07 imac kernel[0]: The USB device HubDevice (Port 1 of Hub at 0xfa000000) may have caused a wake by issuing a remote wakeup (2)

May 18 18:45:07 imac kernel[0]: The USB device Keyboard Hub (Port 3 of Hub at 0xfa100000) may have caused a wake by issuing a remote wakeup (3)

May 18 18:45:14 imac kernel[0]: The USB device Apple Keyboard (Port 2 of Hub at 0xfa130000) may have caused a wake by issuing a remote wakeup (3)

May 18 18:45:14 imac kernel[0]: 589.681427: performCountryCodeOperation: Not connected, scan in progress[0]

May 18 18:45:14 imac kernel[0]: 589.681440: performCountryCodeOperation: No scan in progress, disconnect VAP

May 18 18:45:14 imac kernel[0]: 589.681442: setDISASSOC from ATH_INTERFACE_CLASS disconnectVap

May 18 18:45:14 imac kernel[0]: HID tickle 389 ms

May 18 18:45:14 imac kernel[0]: Ethernet [AppleBCM5701Ethernet]: Link up on en0, 1-Gigabit, Full-duplex, Symmetric flow-control, Debug [796d,2301,0de1,0300,c5e1,3800]

May 18 18:45:15 imac kernel[0]: en1: 802.11d country code set to 'DK '.

May 18 18:45:15 imac kernel[0]: en1: Supported channels 1 2 3 4 5 6 7 8 9 10 11 12 13 36 40 44 48 52 56 60 64 100 104 108 112 116 120 124 128 132 136 140

May 18 18:45:15 imac kernel[0]: [ffffff8019da5400][BNBMouseDevice::init][70.12] init is complete

May 18 18:45:15 imac kernel[0]: [ffffff8019da5400][BNBMouseDevice::handleStart][70.12] returning 1

May 18 18:45:15 imac kernel[0]: [ffffff801feff600][AppleMultitouchHIDEventDriver::start] entered

May 18 18:45:15 imac kernel[0]: [ffffff801c0e6300][AppleMultitouchDevice::start] entered

May 18 18:45:15 imac kernel[0]: [ffffff8020178000][BNBTrackpadDevice::init][70.12] init is complete

May 18 18:45:15 imac kernel[0]: [ffffff8020178000][BNBTrackpadDevice::handleStart][70.12] returning 1

May 18 18:45:15 imac kernel[0]: [ffffff8019d7ca00][AppleMultitouchHIDEventDriver::start] entered

May 18 18:45:15 new-host kernel[0]: [ffffff8020a78d00][AppleMultitouchDevice::start] entered

May 18 18:45:15 new-host kernel[0]: en1: BSSID changed to 10:9a:dd:85:1e:89

May 18 18:45:15 new-host kernel[0]: AirPort: Link Up on en1

May 18 18:45:15 new-host kernel[0]: en1: BSSID changed to 10:9a:dd:85:1e:89

May 18 18:45:30 imac kernel[0]: en1: BSSID changed to 10:9a:dd:85:1e:8a

🙂 AT THIS POINT I MANUALLY START THE TIME MACHINE BACKUP

May 18 18:46:32 imac kernel[0]: AppleSRP started.

May 18 18:46:33 imac kernel[0]: 675.548516: ath_reset: unable to reset hardware; hal status 17

May 18 18:46:35 imac kernel[0]: 676.846986: ath_chan_set: unable to reset channel 136 (5680Mhz) flags 0x10100 hal status 17

May 18 18:46:36 imac kernel[0]: 678.269657: ath_chan_set: unable to reset channel 140 (5700Mhz) flags 0x10100 hal status 17

May 18 18:46:38 imac kernel[0]: 679.696815: ath_chan_set: unable to reset channel 100 (5500Mhz) flags 0x20100 hal status 17

May 18 18:46:40 imac kernel[0]: 681.724471: ath_reset: unable to reset hardware; hal status 17

May 18 18:46:47 imac kernel[0]: AirPort: Link Down on en1. Reason 16 (Group Key Handshake timeout).

😠 BAM! WIRELESS NETWORK DOWN!

Can anyone try this too? Wake up your iMac, check that your connection is up, and then start a Time Machine backup and look for the connection to go down immediately?

I have an iMac (2,7 GHz, i5) that has exactly the same problem. After waking up from Sleep mode most often my iMac could not connect to my router over WIFI. I needed to restart my iMacto get WIFI working again.

However, also the following solution thusfar (1 day now) works for me:

go to System Preferences>Energy Saver and tick the "Wake for network access" tick box.

Not what I want, but if this works until this bug is fixed, it's OK for me.

Same problem here with my iMac 21.5" (mid 2011) in my AirPort Extreme network. I also changed the network location. The option "ask to join new network" was not checked in the first place, so this can't be the problem. Furthermore, since it said in the update description to 10.7.4 that it would deal with SMB sharing, I deactivated that, too. Since then I didn't have any problems so far (hope it'll last).

But just to make sure that Apple will deal with this in the near future, I sent a bug report about this (which we should all do to be heard.)

http://www.apple.com/feedback/macosx.html

After further experiments with Time Machine, I think I can conclude that Time Machine is not triggering the bug. I disabled Time Machine altogether, and after three sleep/wake cycles, the error came back.

Also, IMHO most of the "weird" suggestions on the net for fixing this issue is either based on fixing the year-old bug with Macs dropping the WIFI connection (remedied by turning the Airport off and on), or based on the fact that the originator of the fix is cheated into believing that his/her iMac actually goes to sleep when testing the fix. I have been cheated several times during this bug hunt - the display turns off, but the iMac never goes to the power off state (sometimes because Time Machine is preventing the sleep mode due to the missing WIFI connection), and therefore the error does not show. As far as I can see, the iMac needs to power off for the bug to show. One trick is to turn on caps lock and look for the caps lock LED to turn off (if your keyboard has an LED, that is).

Is this bug found on 2011 iMacs only? Maybe combined with Airport Extreme/Express? Hopefully, there will be enough unhappy customers for Apple to look into the issue 😕

Same problem.. Even after a restart he doesn't connect to wifi.. Have to use cable again 😢. When I restore to 10.7.3 with Time Machine do I also lose my documents created in between? Thanks!

In my case it's even worse. After updated to 10.7.4, My 17" macbook pro could not see the ssid from my d-link router but it could see the ssid from the neighbours after it wake up from sleep. I tried to reboot both of the mac and router many times but the problem has yet not been solved. Can anyone pls help?!

BTW, my ipad and andriod mobile phone work fine!

That's interesting evihill, but it seems like a different problem than others on this thread are having. For most its only iMac that are affected, we cannot see any SSID (including our neighbours) and rebooting the iMac clears the problem. I am not sure that those on this thread will be able to help . . . but worth a try . . . you have my sympathies for what its worth!

Good luck

Spent a long time on the phone with Apple technical support yesterday and - so far - about 25 hours with no repeat of the problem so here's what they had me do:

My set up: Time Capsule and iMac 27" (2011 model).

1. First update the Time Capsule firmware NB the need to do this does not show up on Apple Software update so you have to check independently and then restore Time Capsule to factory settings and set up from scratch (use Airport Utility for this).

2. Trash the SystemConfiguration folder in the Preferences folder in the Library in Macintosh HD.

3. Restart.

So far, so good, 25 hours no loss of Wifi, if the problem reoccurs I will repost.

Thank you for your reply guydominy, i am wondering will i loss all my system config if i trash the systemconfiguration folder?

On MacBook Pro, I started having comparable problem after updating to 10.7.4 -- it doesn't automatically take me into my preferred wi-fi network when I wake up the computer. I have to get it to look for networks, and then I have to choose a network from the list that it creates anew each time. It hasn't dropped me once I'm connected, but the ability to get me on automatically has been lost.