Q: iMac drops Wifi connection after 10.7.4 update

Got mine sorted. Bit brutal but this worked. Saved all my photos and important stuff. Then did a reinstall. Upgrade to mountain lion. Job done brilliant. Mountain Lion is pretty good.

I have the same issue!!!!!! I don´t belive it.. When I have Lion, I resolved the problem with an updated (http://support.apple.com/kb/DL1501), but this is not avaliable for Mountain Lion, so... what we can do?

No update for 10.7.4 users, eh? I'm getting wifi dropped while I'm surfing the web! It's ridiculous... How bad is this for the people who recently converted to Mac from Windows! My Windows friends are going to give me such a bad time about this one.... ugh...

I use 10.7.4

seriously just delete your preferred wifi networks and re enter them.

I have the same issue with my iMac (mid to late 2011, running 10.7.4). WIFI peroidicly drops.  I always thought it was due to my router being upstairs and my Mac down stairs.  The drops would happen every few days.  But recently, the drop offs have been happening about every 30min or less.  The wifi icon shows a connection, and when I click the icon, my network shows as if connected and other networks in range also show.  My only solution is to click 'turn off wifi' and then click 'turn on wifi'. 

I also though it was my provider(I'm using Clear) but every time the iMac losses a connection my iPod, windows laptop and voip phone have a connection(same router).  I have tried some of the fixes listed, but none really work.  I am going to move the router, it this dosn't solve the problem I will end up pluging in.

has worked for me. cheers

I deleted preferred networks and it didn't help. Wifi dropped out on me SEVEN times in a one hour period last night... While I was in the middle of downloading an album on iTunes Store! Freaking infuriating. Router/Airport Extreme works great for my phones, laptops running older OS... And my 2011 iMac was fine until I upgraded to 10.7.4.... It's the OS, I'm sure.

The worst part about all this is that Apple doesn't know how to fix it. Really shakes my confidence in them.

Also, at least one message suggests that the problem persists in Mountain Lion.  So there's been no fix and the drop problem may have been carried into the next OS.

Mountain Lion completely eliminated my problem? Not only am I consistently able to use Sharing without fail, I have also been able to put back the security on Sharing. If you have a mid-2011 iMac, I urge you to spring for the $20 and upgrade to Mountain Lion. I do not think Apple is going to issue a fix for 10.7.4.

So far Mountain Lion also eliminated my problem. I didn't have a any dropout's since i updated osx. This is first time my iMac have been this stable since the first alu model get on the marked.  I keep X my fingers

I suppose I'll have to drop the $20 for mine and my wife's Macs... the money and the Facebook integration were the only two things keeping me from upgrading anyway. I will upgrade and post my experience here. (I've been Facebook-free since May 2011!)

ML seems to have fixed my Wi-Fi drops.  I haven't noticed any since upgrading last week.

I upgraded to ML on 7/28, and I haven't had any drop in connection since. Looks like it solved my problem. Before this, I was having to turn my wi-fi off and on every few minutes.

I have a mid 2011 27" iMac,  and I did not do a clean install of ML. After downloading ML from the app store I just ran it from within Lion.

The problem is not of that type that You only have to turn Wifi on and of. If You have the real problem You hve to reboot to get back Your Wifi. THAT is anoying and still a big problem since 10.7.4. Anyone else with the Big problem solved by upgrading to 10.8 ? I will test it now also and come back with information. Talked to Apple Yesterday and he wanted me to test my iMac 21,5 mid 2011 with another network. If it doesn´t work there either he said that my computer had to have a service. Brought it to my work for a couple of days for testing and here it has worked well ??? Maybe it is a frequence at home that interfear with the 2,4GHz or 5,0Ghz band.

Anyone else tested on another network ?

It worked for me as well so far! Have had the same problems as Winbo wrote down below.

But now it seems to be solved in any way for os x ML