iMAC 21" WIFI failing after 10.7.4 update

I have the same problem: iMac from 2011, wifi drops unexpectedly after upgrade to 10.7.4

The one thing that did work for me was to downgrade the wifi driver to the previous version. Mac OS X 10.7.4 ships with a new version of IO80211Family.kext (version 4.2), that I had to replace with the one from Mac OS X 10.7.3 (IO80211Family.kext version 4.1.2 if I remember correctly). You can find IO80211Family.kext in /System/Library/Extensions. The old version, you have to take it from a Time Machine backup or search the net for it.

So I haven't necessarily had an issue with the wifi dropping (frankly haveb't used it enough since the last update) but rather with the machine not "auto connecting" to my network on boot. As you know, 10.7.4 adds the option to uncheck the "reopen windows next logon" feature. Well I found a direct correlation between having this checked vs. not checked.

When checked, the machine automatically connects.

When not checked, I have to go find my connection in the wireless interface.

It's as if the wifi service is being considered a program and not reopening when the option is not checked.

Mind you I'm very new to MACs; however, this seems awfully coincidental to me.

Similar problem here with a 2010 iMac. Random drops from the wifi connection. My iMac was at the Apple Store for 3 days of testing. Conclusion -- problem could not be replicated. Apple did not acknowledge that 10.7 has connection issues. That seems to go against the number of complaints in this forum and others.

Possible short term fix:

Same issue. Mid 2011 iMac. Updated to 10.7.4 and wifi dropped. The iMac could see any SSID until it was rebooted. My MacBook Air, iPad and iPhone all fine.

I went to Apple tech support and like others was faced with a slippery resistance to the idea that this was anything to do with 10.7.4.

Eventually it was suggested I reinstalled Mac OS (switch off, switch on with cmd and R keys held down. Then follow the process. I wasn't hopeful but was compliant. Imagine my joy when, on coming back to me my iMac asked if I wanted to update to 10.7.4. Of course not!

So reinstalling Mac OS takes you back to 10.7.3. So far so good. Will keep you posted.

Still hoping fpr a proper fix from Apple but they don't seem to be taking seriously

in contrast just updated Omin Group's Omniplan (BTW this is great software for the Mac, check out their offering if you haven't). The update notes:

"It seems as if our fix to the Task: Schedule Inspector in 2.1.1 actually caused more widespread crashes. We've rewritten this code in a more robust fashion and have not seen this problem reappear"

Owning and fixing the problem - Apple guys please take note!

good luck

Guy

Thanks.

To clarify -- I moved from 10.6.8 to 10.7.4 (avoided Lion as long as possible).

Apple Store diagnostic tests showed all systems normal including wifi. I gave them permission to archive my data and reinstall the OS. Following this they concluded they could not replicate the wifi drop problem.

Upon returning home I learned that Apple Store had reinstalled 10.7.3 and not notified me they were giving me a different OS version than what I had delivered to them. Be that as it may, the wifi connection problem was still present. I installed the 10.7.4 update and the wifi problem persists.

Now my problem disappeared.

EVERYONE,PLS PROVIDE WHICH ROUTER AND WHICH ENCRYPTION DO YOU HAVE!!!

Did you tried:

1)delete network settings for this network

2)restart touter

3)use WPA2

4)is it happens with other routers ? (for those who have laptop)

My MBP mid 2010 i7 have the same problem with wi-fi in Os X 10.7.4

The behavior is that the network is working for a while but suddenly is Wi-Fi Signal Status completely empty. I need to go in and select the network again. Often loses MBP Wi-Fi directly, but the third time will keep the MBP signal until I restart the computer, then precessen same again.

I have tried is to delete the network and add the network for OS X also resetar (Netgear WNDR3700), and no help

And yes it happens on other routers!

Does anyone know what to do?

which type of encryption?

WPA 2 is my encryption

and if you disable encryption at all?

Apple had my iMac for 3 days. They were unable to replicate the wifi drop problem on their site. They reinstalled the OS. This did not solve the problem. Apple did not acknowledge there is a wifi drop problem with Lion. Seems like we can only wait for them to address.

I waved the flag of surrender and wired an ethernet cable from my router to my iMac.

Just put it to "never sleep" that way you can loose the wire!

Same problem. Mid 2011 iMac, Time Capsule, I am going crazy with the wifi dropping!

In the middle of important work email wifi dropped for the 100th time!

Everything was great until the last osx update.

Does anyone know how to return the Mac to update before that?

And if I dont remember the exact date ( I know that it was one week or so) how can I find out when did I install this sh***y update?

Why is Apple so negligent and how did they allow this to happen?

I will not reinstall osx.

Apple, do something!

Serge -

The wifi drops do not necessarily follow sleep or suspend. As with others they occur randomly during use -- in the midst of creating an email or editing a photo e.g.

Phil

Kirill -

Please verify that you took the steps listed in your message and this stopped the wifi drops. Thanks.

Phil