iMac 2011 - no wifi connection after sleep under Lion

It's hopeless...

I tried all tricks mentioned in this thread, but in vain. Each trick works for a limited time, but then the problem pops up again.

While at first my iMac lost the wifi signal after waking up from sleep, I now have the problem after restart. As a result I need to restart my iMac a couple of times before it's willing to hold on to the connection.

And no, there's no problem with my Apple Basestation. Connection with all my other Apple devices work like a charm...

With Mountain Lion in the pipeline, I guess that Apple won't be doing much about it and just see what it gives when we installed the latest MacOSX version.

Strange too that Apple doesn't acknowledge the problem.

Has MacOSX complexity outgrown Apple's capacity?

Has it reached the level of stability of Windows I used to know when I switched to MacOSX from the moment it was announced?

C'mon Apple, don't let me down now!

Mountain Lion tomorrow.. hope our problems are solved.. 😕

dropped 3 times in 15 minutes this morning. Where as it worked fine yesterday. all conditions the same, weird.

Though i havent got utorrent open at present.

After months of suffering the bad WiFi connection, lots of calls to AppleCare and tests I finally got my iMac WiFi to work as expected.

The solution is Mountain Lion. After the update no problems anymore. WiFi connects allways after sleep.

I'm very upset with Apple becouse after lots of calls to AppleCare, they assured me that this was not a fault of my iMac they can't do nothing and I need to change my WiFi router.

Very strange as I had 4 iPhones, 2 iPads, 1 notebook, PlayStation 3, iPod Touch, PSP, my smart TV and AppleTV all connecting perfectly via WiFi to my router, that has been working flawlessly for years, and the problem is not from my iMac but the router. Sure!

Now after installing Mountain Lions my router has been finally repaired. Thanks Apple! 😠

Tried as suggested by another user to uncheck the "Ask to join new networks" field under network preferences. Viola! worked instantly.

Mountain Lion upgrade aggravated annoyance of the discussed interference of WiFi and Bluetooth, for me. WiFi appeared more stable, but connections to the mouse and trackpad started to drop periodically. Wost of all, when the computer falls asleep itself, it does not wake up with keyboard or mouse anymore, and becomes unresponsive for up to a minute or so, when woken up with the power button, before keyboard and mouse reconnect. The long waking up annoyance disappeared completely once I disabled WiFi; connections to mouse and trackpad still drop once in a while, but less often. For now, I keep WiFi disabled and use eithernet till next set of upgrades.

I was having the same problem after installing Mountain Lion.

What i did was in Finder went to /Library/Preferences/SystemConfiguration/ and deleted all the networking plists (refer screen shot). Then restarted the Mac and in Network Preferences reconnected to my WLAN.

That solved the problem.

I tried this and it did work for around the first day or so, but then wifi connection began dropping out again on iMac with Mountain Lion, where wifi has been fine all day on Win7 laptop and other connected devices.

Oh well, we await a proper Apple ML Wifi Fix release...

I can confirm that. Mine was working fine, until I reactivated the Internet sharing. The Problem is back. After sleep MBP won't search saved WLAN connections and connect.

Yeah wright.. I'm waiting since Lion 10.7.4.. And I still see in the 10.7.5 or 10.8.2 dev updates.. NO KNOWN ISSUES!!!

The same issue for me.

iMac 2011, 10.8.1 is installed.

I have Time Capsule + iphone + ipad + macbook air + iMac.

The problem is found only on iMac😮

thax \ it works for me. sys.pref>network> Location>add location \ change name from automatically to Home.

I have had this problem since I brought my new iMac approx. 9 months ago. I have tried all suggested solutions but nothing worked for me until last week. I decide to forget wifi and spent £50.00 on getting my master telephone socket move next to my Mac with the latest master socket and use ethernet cabling. Having done this I installed the latest Apple software update which partly consisted of improvements to the wifi reliabilty. I disconnected my etherent and since then, about 5 days, I have had no problems with wifi connection, it has been 100% reliable. My problem now is, I don't know whether the fix was down to repostioning of my mastersocket/router or was it the latest software update but hey who gives a s@@t its working at long last🙂

If it was the Apple software update why, oh why, has it taken so long, if it wasn't then my 50 quid is money well spent although I feel like billing Apple.

I have same pb

my configuration

Imac mi-2010 under moutain lion, last version

A box connected by ethernet to an airport extreme
and my Imac connected by wifi on airport extreme

and when Imac is disconnected, all my "ipad, nas, apple tv, tv,..." doesn't have access to internet

I have to reboot

Plse help me

Is it just me, or have the latest updates finally fixed this? I've had no problems for a few weeks now, and there's been no real traffic here for a while.

After all the complaining we did, I thought it would be nice to acknowledge that. After all, it only took a little over a year to fix! Must have been a tough one for the engineers.