Q: iMac 2011 - no wifi connection after sleep under Lion

I'd agree with that Krizbleen.

My iMac 11,2 is a mid 2010, 21.5" model, now running clean install of 10.7, upgraded to 10.7.3 and with recent firmware upgrade (for recovery via web connection).

On 10.7.1 and 2 I could get intermittent reconnect to wireless AP when resuming by mouse or keyboard click. Often it would resume a connection for a few seconds then drop out (saw this by running a ping).

On 10.7.3 it will only reconnect to wireless AP after resume from sleep using the power button, not mouse or keyboard. The reconnects are permanent.

I also dual boot ubuntu 12.04 Alpha 2. That always reconnects after resume, but it only resumes by the power button, not at all with the mouse or keyboard, so it's similar behaviour.

Obviously the power button reaches parts that the mouse cannot...

My re- connection issue began Feb 1, 2012.  Was there an update causing the problem with anyone else?

I also am a bit frustrated after an hour and one half on the phone trying to fix what everyone else has been dealing with for some time.

I recently bought (4 Feb 12) an iMac OSX V 10.7.3 21.5-inch, Mid 2011 and started to experience the dreaded won't find WiFI when woken from sleep as per this thread.  Of all the small tricks suggested in the 13 pages of threads, I found pictonic's note most helpful - that is if you don't use the keyboard to wake up the iMac but instead press the power button to wake it, it finds the WiFi immediately.  So it seems there is some key difference between stirring the iMac from sleep with the wireless keyboard compared to using the Power button.  Given the grief everyone seems to have experienced, this simple change seems a really good work around.  Ideally, for an ex PC user coming to Apple, I expected the damned thing to just work.  I have not had any problems with my Mac Book Air 13 inch connecting to the WiFi network either so it is a mystery.  Anyway, use the Power button to wake the iMac and it seems to quickly find the Wifi and reconnect - problem solved!  Thanks for the steer pictonic.

Thanks for the solution youseful and particularly thanks to pictonic. I have a mid 2010 iMac 27 with Lion 10.7.3 which was updated on Feb 9, 2012. That was when the post sleep - no wireless reconnect issued started for me. I  downloaded and reinstalled the 10.7.3 update again but that made no difference. Now when I wake up from sleep with the power button, it reconnects every time. As stated previously in these posts, it appears that when the sleep command is invoked, the entire system is responding as a total system shut down. Trust the engineers in the Apple labs are busy developing some new code.

Thanks again for everyone's input and hopeful that this will work for as many of us as possible in the interim.

bandmk1010

Thanks for the feedback

Note - I just checked the OSX V 10.7.3 update summary and see below link and extract - it was specifically aimed at "resolving a wifi connection issue when waking from sleep" and an issue "preventing Safari from opening before joining a wireless network"!  It looks like they missed their mark and by some margin. 

Also given this thread started in mid 2011 and 2 versions back, it seems the problem has lain unresolved for some time now, not just topical to V10.7.3. 

I should also give credit to Krizbleen who pictonic replied to as Krizbleen was the first post that mentioned using the power button.  You're a lifesaver mate!

http://support.apple.com/kb/HT5048

Additional Information

What's included?

The OS X Lion v10.7.3 Update includes Safari 5.1.3 and fixes that:

• Add Catalan, Croatian, Greek, Hebrew, Romanian, Slovak, Thai, and Ukrainian language support
• Address issues when using smart cards to log into OS X
• Address compatibility issues with Microsoft Windows file sharing
• Address an issue printing Microsoft Word documents that use markup
• Address a graphics performance issue after sleep on some earlier iMacs that use ATI graphics
• Resolve a Wi-Fi connection issue when waking from sleep
• Address an issue that may prevent Safari from opening before joining a wireless network
• Fix a potential issue authenticating to an SMB DFS share
• Include RAW image compatibility for additional digital cameras

Hi, I was experiencing this problem from one year. It seems was solved with 10.7.3 but after the insertion of another new access poit on the list the problem is out again.

I mooved the access poit from 1st to 2nd place it's SOLVED. I hope I never had again this problem that's VERY ANNOYNG

hope help's someone else

bye

After almost 2 years without problems with my late 2009 iMac I have also this weird problem with the WiFi connection.

I think it's not related to Lion or 1.7.3 update. I was using Snow Leopard and then updated to Lion and I've been using my iMac for months without a single problem when connecting to my WiFi network.

The problem appeared when I changed my WiFi security settings from WEP to WPA2. Just after the change the problem was there. Always failed to connect after wakeup from sleep. Then I checked my network settings and I noticed that on the networks settings still appears as WEP, so I removed completely my WiFi network and configured again. Now it appears as WPA2, but still fails when reconnect. Some times it connects successfully, but 80% of the times it fails and I have to connect manually. It's very annoying!

When I saw in 1.7.3 update that it solves the problem when connection from sleep I thought it was the solution. But after the update nothing is fixed and I'm still having the same problem.

I hope we got some solution to this problem soon.

Regards!

I agree.

I've tested this method, with my iMac 27" : to wake up only with the power button.

It 'repaired' the connexion.

I really wonder what is the problem, since with the 10.7.2 version, I had really no problem.

This ***** from Apple, really !

They know the hardware (unlike Microsoft PCs) and the OS, why can't they fix it ?

I really hope in the next update it will be fixed forever

One more issue; If you are listening to ITunes on a wireless sytem, and your Mac goes to sleep, you will disconnect when trying to awake.  A bad dream.

Here we are again. This f....ing problem makes me mad.

I think that apple engineers can't read a protocol.

I don't understand why with 2.4 GHz all works good and not with 5GHz.

Maybe I will be old and my macbook will hangs getting out of sleep

I'm very hungry with apple; till leopard everithing working fine after I have a lot of problems.

This actually made my problems worse. Instead of waiting to be connected to my network from sleep, it just does nothing at all. Now I have to manually select my network to connect to it every single time!

Thanks,  I checked the link, my machine was produced several months after that recall. 

I never had this problem with no WiFi connection after sleep, untill I downloaded the update on Sunday 12th February. The wi fi will only re connect via the power button.

What on earth is going on with Apple, to try and fix an issue for some that had one with this, that hasn't worked; only to have created an issue for others that never had one before.  

The suggestion to wake from sleep using the power button (mid-2010 iMac 27") is a good one. The wifi connects to the base station (a new Time Capsule) if it wakes that way. If I wake the iMac by clicking the mouse or keyboard, the wifi searches for a few seconds (as evidenced by the icon in the top right of my screen), but then quits. In that case, I have to click the wifi icon and select the network before I get a connection.

This problem is new within the last few days for me, i.e., since installing the Time Capsule with its new wireless router. Before that, I never noticed a problem with an older DLink router.

One problem is that Time Machine is supposed to wake the iMac to do backups, which are not happening, because the network isn't being reconnected when Time Machine wakes the iMac up. However, even more strangely, the Time Machine backups DID occur the first night the Time Capsule was installed (2/12/12).

I have no idea why waking the iMac by pressing the power button would get the wifi to correctly connect whereas waking it by pressing a key or the trackpad (or, apparently, a software wakeup from Time Machine) does not work. When I wake it by touching the keyboard, it clearly "sees" the available networks. One of them is my home network, the other is a neighbor's secured network. I don't know why it doesn't automatically choose the network it was last connected to. The Network control panel is checked to "remember networks this computer has joined".

This kind of dinking around with computers is so 1980s when everything was like this. You'd think that in 2012 a company that's worth a half-billion dollars could get networking on their own equipment right. It's also irritating that no one from Apple seems to be on these boards to even acknowledge that there's a problem and they're working on it, and perhaps offer an apology to the customers for the inconvenience caused.

I agree. I have the same problem for about one year an half. I have a macbook pro late 2008 so I think that this problem is quite common and I'ts incredible that Apple, using controlled hardware and costing 30% more than generic pc, can't solve a problem that seems very simple. I have to set on and off the airport and all the 2.5GHz networks works but I can't see 5GHz network. After I shut down and restart wi-fi interface 3-4 times it magically set up the connection at 5GHz.

It's very disappointing .....