haven't had the problem here..
My wifi works fine, even after shutting down, closing te lid, whatever...

 Yep, a lot of people don't suffer this problem, but there's many who do - hence the NYC decision, so I'm not at all jealous for Apple engineers trying to figure the problem out, but equally I feel sorry for Mac users who are watching the warranties on their new Macs slowly move to expire but who don't yet have stable WIFi access, you know?

I have been seeing this- I have an Airport extreme with 802.1n and a macbook pro- when my brother came to stay with me with his macbook pro (both with 802.1n) the network conks out all the time, especially when one or the other joins the network. very frustrating. All we can do is turn the router on and off. I just updated the router firmware, and hopefully the next OS X update will rid us of this annoyance.

I have an MBP 17" 2.33, and the WiFi is sporadic, at best.

My net connection conks out when I open the lid. I get around it by shutting Airport off (on the mac) letting it sit for 10 seconds or so, and then turning it back on.

It's irritating - but hardly debilitating.

It was solid in 10.4 - no issues, whatsoever.

We've been experiencing this problem with our Macs and our Belkin 801.11N router, particularly after restarting the Macs. At startup, the Mac reports that the wireless connection previously used is unavailable. On one occasion, when attempting to reconnect to the network, it prompted for a WEP security username/password (despite no WEP security enabled on the router). Eventually, after several attempts to connect, it finally established connection and worked as usual.

On another occasion, we were streaming live video for about 10 minutes when the Mac lost wireless connectivity. Had to reboot the Mac to get it back online.

I'm actually glad to see that this is problematic for others. I was afraid I was starting to lose my mind. ;-)

My Tip:

Don't buy an OS that just came out (especially if you depend on it to keep your Cashflow goin). It's that simple.

Second Tip:

Get a Test Machine...

I have various machines in work I look after on 10.5.2 connected to cisco APs in G mode, no probs.

I also use my mac and my wifes at home on pure wifi N - apple extreme with attched time machine and works a treat, no drop outs , perfect.

I'm still running Tiger 10.4.11 and I'm having consistant Wireless connectivity issues as well_

Unless the problem was also added to the 10.4.11 update - which could very well be_

Otherwise - I'd have to put my money on one of the 2 Wireless updates since the start of 2008_

I wasn't having problems in the fall - then I started having problems - then it stopped and now it started up again_

I just click join another network and then enter my hidden SSID and type or paste in my WPA* security and it works again. I know it is annoying but it beats having to reboot the router or do other bizarre things.

History:
I also thought it was my router until I tested with my old Powerbook (Tiger) and my Ubuntu Thinkpad and both were still connecting fine.

I hope that helps others until the gremlin is found and shipped backed to Redmond.

I was having this problem after updating the AEBS firmware, intermittent drops and occasional requests to access the keychain. After trying everything I could think of, I went into airport admin and clicked the "wireless options" button. In that menu there is a box for "Use Wide Channels." By default it is checked on the n network. After unchecking and restarting the AEBS, the problem disappeared!
I didn't even have to restart the computer. Since this discovery, I have made changes to the AEBS and restarted, only to discover that the network drops again. Sure enough, if I go into wireless options, the "wide channel" box has been re-checked! Unchecking the box makes it all work again :)

I have a 17" powerbook 2.4Ghz, a 12" powerbook, a Mac Pro 2.66 dual, an Imac and a iphone all running fine on three different networks with no problems. Also on the network are three PC machines.

All of my machines are up to date with the latest OS and all software updates. Weird how this is only causing select machines to have issues. Hang in there, maybe the next software patch will fix the issues.

just something to ponder:

i recently upgraded 2 hard drives in 2 different 15" macbook pros... purhased about 1 month apart... and noticed 1 had a dark blueish "n" card.. and 1 had a silver "n" card.

both were recently upgraded to leopard... only the "silver" card was having trouble with the "same exact" network that worked fine on Tiger.

so the moral of the story is apple is using different wireless cards in the exact same units, thus seemingly "random" problems are somehow tied to the n cards installed.

-

i have mbp and leopard and my gf has a vista and we have problems with my airport extreme. i have unplug and plug the router to print or play music wirelessly.

Seen this a few times but just opening Airport Utility seemed to stabilize it. I've seen some issues like this on older models and OSes depending on the degree of security being implemented too.

With a D-Link "G" router I have at home my Wifi connection on my macbook won't stay connected for more than about 20 minutes, then the only way to get it running again is to turn off the airport card and turn it back on.

I've got a Linksys "G" router as well and I don't have the problem with that one.

I've noticed the issue when connecting to Linksys routers but I have had no issue with Time Capsule.

I need to reset my wired router hourly.
and that really bothers me...

There is a problem with macs with broadcom 802.11n chipsets and the wide channel mode of 802.11n routers. If you turn wide channel off, this should stop disconnects from happening when you use a large amount of bandwidth at once. I did this and didn't see any drop in my wireless speed. YMMV.

I'm having similar issue with my Apple TV.
Wireless connection works fine for 1 or 2 days, then it get disconnected and I have to re-configure the wireless again.

My MacBook developed the problem of dropping wireless connections. It'd be working great, and then, suddenly, connectivity would be lost. Toggling wireless off and then on again (via the menu bar) would usually address the problem for a few hours.

It all seemed to clear up with the latest MacBook firmware update. Since that installation, I haven't had any problems related to Wireless connectivity.

I just started having the same problem of disconnected wireless with Tiger. A hard restart of the Airport Extreme seems to do the trick. It seems, intuitively, to be router related and not OS related. Tough to tell.

I have the problem with the dropouts. My 10.4.11 powerbook is fine, my two leopard machines (one an upgrade, the other new) both exhibit the problem. Doing all the things suggested on forums doesn't fix it permanently. It's a total mess, especially since I convinced my wife to switch to a macbook from her pc. Freakin fix it already apple! And I should note, Apple's been deleting threads from their support forums.

I had these same issues of Leopard dropping my WiFi connection seemingly every couple of minutes. And then I reset the password, the station name and the new Apple WiFi base station at the same time and now all is well. It never drops a connection now.

I have problems with Airport not connecting to WEP networks very well. Takes a few tries with connection timing out or just not connecting at all. Disabling Airport (on the mac) usually works but not always. I dread closing the lid once I'm connected. Not usually any problems with no WEP though.

I've only had one recurring network issue, but manually setting the wireless channel has fixed that issue and it was only affecting the old G4 iMac. The other 5 machines have always run fine.

I have all sorts of issues with WPA Enterprise. Sometimes on boot up it will connect, sometimes not. Sometimes it will reconnect after waking from sleep, sometimes not. Sometimes turning Airport off and back on after 20 or 30 seconds will fix the problem, sometimes not. At home with WPA Personal, the system is solid as a rock even under marginal signal conditions.

MacBook Pro 2.2 gHz OS X 10.5.2

My new MacBook (purchased in January) was dropping the wireless connection very frequently. Oddly enough, another Mac (Mac mini) was working fine.

Eventually I experimented with several different non-Apple four different routers (Linksys a/g, Dlink a/g, Netgear a/g & n). The MacBook dropped its connection consistently with any router in the "G" mode, and also wouldn't work correctly in the "n" mode.

I replaced my router with an Airport Extreme 'n' and everything has been working fine for me since.

So I presume it was some issue between the new "n" hardware, and Leopard.

Whatever the source of the problem, it is common to both Leopard 10.5.2 and Tiger 10.4.11. I have a proven, secured, wireless system that had no problems until updating to 10.4.11. Within 1 hour of the update, I had to reboot the SMC router. Connection is an off and on thing. Sometimes connection is as it should be, other times a router reboot or two is required. If ALL security measures are removed, connection is always made...but I will not run an unsecured network.

SMC says my router is "end of life", so they are of no help. If they think I'm throwing away a still functioning router, they're nuts. They are also nuts if they think I'm ever going to get another SMC "anything".

I think Apple broke the seamless wireless functioning with something they've done regarding security. If that's the case, Apple needs to FIX IT.