I think Carlos hasn't heard my scenario.
Snow Leopard - never dropped a wifi connection.
I upgraded to Lion, wifi drops every 1-2 hours.
I tried all the solutions I could find. Always the connection drops every 1-2 hours for over 1 month.
I reverted my system to Snow Leopard... huzza! Not a single connection dropout after days/months.
Just today, I clean-installed Lion on a spare partition. 10.7.3. After 2 hours - connection dropout. Requires restarting Airport to fix.
I booted back into Snow Leopard. No problems. No dropouts, ever.
And here I will stay.
Snow Leopard - good, Lion - bad.
There's no need to check my router or my internet service provider. Because Snow Leopard works perfectly, hence this rules out any problems with those devices.
Just got off the phone with Apple technical support, they are aware of the issue, a HUGE number of people are having it, not just iMacs, but the laptop community as well. The only ones not affected are the iOS 5 people, like on my iPad, which connects instantly everytime, and I have about 15 different places I connect with this thing. That's what ****** me off so much about this, is that my little $500.00 iPad goes "blink, I'm on", instantly, everywhere, 15 different locations, and my $2500.00 quad core i7 iMac with 12 gigs of ram sits there hunting for half a minute for the ONLY wifi thing in the area.
Anyway, folks, they ARE working on it, and there's a BIT of a workaround which will speed things up for some; instead of waking the machine with any wireless device (mouse, keyboard), wake it with the power button - click for one second and release. My machine only hunts for about ten seconds this way, as opposed to almost thirty seconds any other way.
The technicians are aware of it, they acknowledge it's a software problem, and there will be a software solution soon.
From the horse's mouth.
PS thanks to those who've TRIED to help.
Thanks for the good news Cameron.
I've been a PC user all my life. I just bought an Imac 27" with all the bells and whistles an absolutely hate this thing. Apple tech support has been worthless. After having me trash all my preferences, settings and still got no resolution. When they couldn't fix the problem, they told me it has to be my router (which is on the table 6" away from my Imac). I informed them that my PC still works just fine and therefore it must be the mac.
The only way I've resolved this issue is permanent connection with ethernet cable to my router.
It is not a hardware problem as some people here are trying to tell us...
Apparently they don't have a clue what they are talking about..
You don't even need a Cable or DSL modem to have a wireless network in your house.
So you can eliminate those as the problem from connecting to your wireless network...
If other devices can get on your wireless network, then there is nothing wrong with your network...
I have been trying to help a friend with a brand new Airport Extreme 5th generation and a brand new iMac...
When it wakes from sleep, it cannot find his local wireless network... It will not join it automatically....
He has to manually choose it everytime the computer wakes from sleep.
I had him call Apple today and they told him again, there is a software fix on the way...
Hopefully this is fixed sooner than later....
Good post. This is a very complicated issue with which I dealt with for sometime. Unfortunately, the solution is not an easy one since there are so many different system configurations/hardwares involved. I can't tell you all of the stuff I went through to reach a solution. And, I'm actually not sure what resolved it! I would suggest that pending Apple's resolution that you'll find that Lion likes a wifi 5GHz connection best. Meanwhile, we'll wait.
We have a brand new (~1 month old) Macbook Air that came with Lion. It never resumes the preferred wifi when coming out of sleep. I have to manually select it every time. From this thread it sounds like a Lion bug. Such a strange bug to be in a major OS release. Once it's connected though, it seems to keep the connection.
Also I had the same problem as most in this tread, with my macbook 2009 dropping wifi connection randomly. My basestation is an Airport Extreme. Tried every tips I found without luck.
Finally I changed the "Radio Mode" under Wireless options to "802.11a - 802.11b/g" thus disabling n-mode.
After this the wifi connection has been rock stable. This means that the theoretical throughput of my wifi network has decreased but at least until a better solution is available I can live with this..
Hope this helps someone else..
I also did this, as mentioned earlier.
Disabled n-mode on my router, rock stable connection ever since.
So again for everyone with the "drop-out"-problem:
Go to your router/Airport configuration,
search for "Wireless Settings", change "Radio Mode" or "Wireless Network Mode" to
"802.11b/g" or "802.11G only" or "G Only".
My problem appears to be related, but even worse. My Wi-Fi connection drops after about two minutes, even though the computer does not go to sleep. I have to stop/start Airport to get it to connect again, then repeat, repeat.
I put my Imac on the other side of the room from the router, since I intended it to be connected wirelessly, while my old desktop and Linux laptop connect via cable. Now I have my Linux using Wi-Fi and routed a cable across the ceiling, over the ceiling fan, down to the back of my Imac. This *****! Before this, I was very happy with my Imac.
Woodland, CA, USA
The single only reliable way to fix this for me has been to turn wifi off and use only a wired ethernet connection.
Welcome to Apples little effort in planned obscelecence. How else to get everyone to buy Mountain Lion or other OS upgrade once a year. Just like the Lion removal of Rosetta was a planned effort to get people to buy all new software.
I'm having the same wifi (Lion) problems.
Apple is doing EXACTLY what Jobs criticized Microsoft so harshly for doing.
Like it or not, Apple is becoming MS.
They make us buy Lion to get onto iCloud, when not only is Lion complete crap (it won't work with my Time Capsule), they are getting ready to release Mountain Lion.
By the way...I read Jobs's biography, and he was a complte *****, so these latest actions don't surprise me.