Judging from all info I gathered on this issue up until now, it seems like it's a problem that only occurs when updating to 10.7.3 on Macs that have an Atheros-based AirPort-card and Bluetooth-periferals...
Is that right in your case too ?
If so : disconnect all Bluetooth-hardware like keyboards and mice and restart using only USB-connected periferals. (You might need a SHIFT-restart, for extensions to reset properly.)
You might just be in luck that that will help.
[ if I remember correctly, the Atheros-based AirPort-card not only handles WiFi, but Bluetooth also... so the basic problem might be about Bluetooth and AirPort periferals conflicting because of a bug in the order in which they are being connected... ]
Agree with AMCI71. Issue is with 10.7.3 update. I had zero issues before update. Now, not connecting after sleep issue same as many of the post here. Hope to find a fix in this thread. If not will backup to 10.7.2
21.5, Mid 2011 2.5 GHz i5
CoreWLAN: 2.1.2 (212.1)
CoreWLANKit: 1.0.2 (102.2)
Menu Extra: 7.0.2 (702.1)
configd plug-in: 7.1.2 (712.1)
System Profiler: 7.0 (700.3)
IO80211 Family: 4.1.2 (412.2)
WiFi Diagnostics: 1.0.1 (101.1)
AirPort Utility: 6.0 (600.92)
AMCI71, Agreed with your first assessment. A few pages back and that is why I posted response. I too have an atheros card in my imac, and am currently using a bluetooth keyboard, mouse and trackpad. Never had an issue before the 10.7.3 update.
I am not going to go out and purchase USB peripherals and give that a go. I can understand Toon.B's point on periferals conflincting on start up. But this is all APPLE HARDWARE. If it is a timing routine, then why has this not been a quick fix? I bought into the apple products becuse "It just works" and till now it has.
My issue is not as extreme as some listed in this thread. I just have to manually select my network that has dropped after waking from sleep over a long period of time. Once I do I stay connected without any drops.
For now I will wait on a patch.
Why this issue has not been addressed: Planned Obsolescence.
Why have an operating system that works and what flaws there are get fixed when you can turn around in a year and reskin the operating system and resell it as Mountain Lion just a year later.
There is no economic gain in making a system that works and people do not need to change. There is none. However if you market Lion as being better than Snow Leopard you can make some great profits. Then design Lion to need to be replaced. Replace it in only a year with Mountain Lion and there you have it -- Look, a new iChat renamed to Messages and given a minor code tweak to talk to iPhone users.
We are all the victim of cyclical economics and planned obsolescence. It is why Rosetta was removed. You need to buy new games. It is why your wifi is flawed. You need new routers and new computers. It is why you will be made to feel like you need to buy Mountain Lion.
Like many users, I've updated all my systems to 10.7.3, thus far, my 2010 revision Mac Mini does not drop wifi connection once in sleep mode, I cannot say this about my top end 2011 iMac though - I'm on a Netgear twin WLAN connection and both 2.4 channel and 5 channel keep dropping.
This is a real pain, I've never experienced wifi dropping in any of my Macs until this revision - for those saying revert to USB mouse and keyboard, not an option - I have several keyboards, mice and trackpads and only very old USB equipment - perhaps Apple should provide us with these items FOC, or correct the problem.
I only updated to Lion Christmas time, I'm now regretting I did this, particularly given by the third major update to Lion one would have expected serious issues like this not to pass muster - I trust apple will supply a fix ASAP.
I completely agree with you. The handling of WiFi of Lion is a scandal. I had problems with two different computers (a new MacMini and a new MacBook Air 13') with 10.7.2. I put big hopes on the update, but the same problems continue. Apple leaves us in the dark. After years without any WiFi problem I work now with a cable and fear the day that I have to connect my MacBook Air to some WiFi outside my home. Apple needs to fix all these WiFi problems as soon as possible.
For What it is Worth
I had experienced wifi drop problems after updating to 10.7.2, late last year. It was really frustrating few weeks, which lead to a frantic search for solutions.
I had found an answer in the following link, which I had used. It was successfull, and I never faced wifi drop problem again.
Two weeks back, my imac auto updated to 10.7.3, and wifi drop problems resurfaced again. Initially I didn't realize it was related to the update. However, once I thought it could be, I searched and found that the wifi drop problem is again happening with 10.7.3
Luckily, I had bookmarked the link, and had the local copy of the details of the earlier fix.
I tried the same with 10.7.3, and to my great relief it works.
No wifi drop after this fix applied on top of 10.7.3
My system is 27 inch imac, late 2009 model.
I credit all the thanks to the original contributor of the fix in the link.
As I have seen so many frustrated users venting their ire with respect to this problem in this forum, I want to share my experience and a possible solution/workaround.
Please try and share your experience with this approach.
Seems to have worked for me also in regards to the wifi not reconnecting after waking from sleep. I had emailed this to Tim Cooks email and got a response from a person at Apple who talked to me about it. It was pretty obvious they were clueless on the matter and I am pretty shocked that they are looking at releasing mountain lion and lion still has some serious bugs to squash. At least when Lion came out snow leopard was on 10.6.8 and was stable for those who didn't want to upgrade
Good to hear this works for you !
But a word of CAUTION would be in place :
please be aware that earlier in this thread it is claimed that Apple (a.k.a. 'some unnamed Apple Helpdesk employee') has warned that having drivers and/or extensions of older OSX-versions installed over your current OSX will prevent them from being updated in future updates of OSX...
so... even though you 'solution' may have solved things on the short run, it may as well have put you on the path of new trouble in the longer run...
There is however a solution that has far less chance of future problems, since it installs the same version of the kext-file that 10.7.3 needs : after you have reinstalled the IO80211Family.kext-file from 10.6, reinstall the kext-file from 10.7.2 on it... according to the version numbers you then have the 10.7.3 version installed... (the kext-versions in 10.7.2. and 10.7.3 are the same...) so you have far less chance of getting in trouble again at the next OSX-update...
for some mysterious reason this has worked for others, but only if you've re-installed the 10.6 kext-file inbetween...
the choice is up to you...