Q: iMac 12,2 (mid 2011) airport (wireless) problem

Unfortunately this is something I have already tried with no luck. My router does not support N and instead was set to B/G, which I changed to G, but still no success.

I haven't got my iMac back from repair so far but one thing is for sure:

I won't be willing to pay a fortune for a premium priced computer and then accept "solutions" for a connectivity issue that force me to reduce WLAN speed (from N to G) or security (anything less than WPA2) because the supposed premium product does not perform according to marketed and very basic product features/requirements.

If exchanged antennas and airport card will not fix the problem I will join martinimac's view stated some posts above that "premium price does not buy premium product" any longer at Apple.

In that case the only remaining option will be to return the iMac to Apple and get the money back...

I still think it's a software problem myself.

What I don't get is how long it's taking apple to fix it..

The hardware works fine in bootcamp, and for me after I reboot it works fine.

I agree that we shouldn't have the problem, apple dropped the ball for sure, but I wouldn't return the Mac.

A few of us have been able to get a workaround going, turned airport off and ran wired a few days. For whatever reason it clears out the majority of the problem when you go back to wifi.

Seems like that has been the solution or most of the problems. It was for mine last month when I first purchased the iMac. 

The issue is not 802.11n really, its just that 802.11n requires AES encryption.  Without AES, 802.11n should not negotiate per the standard.

Thus, the fix for most seems to be forcing your router or access point to do TKIP.  Both TKIP and AES work for 802.11a/g.  However, unless you specify on the router to use TKIP only, more than likely its negotiating AES first and causing problems.

The trade-off is that all your other devices on the wireless will need to be changed to reflect the encryption mode change which is a pain.

The work around I did, was to allow only the iMac on the 5Ghz radio at TKIP, and all other clients to stay down on the 2.4Ghz spectrum. Thus only the iMac is restricted to 802.11a rates and the lower encryption method. 

Actually the TRUE solution is to just use Windows on a Mac partition - then your problems with Airport and DVD burning under Snow Leopard 10.6 will be solved !!  The hardware is fine - it is the bloated software which intoduces the problems ...

if the problem has to do with 802.11n, then why are people with the older airport g having the same problem?

It does not 100%  to do with 802.11n or or the radio used. .  However, there is some combination of 802.11n (which requires AES) and the drivers that cause problems.

Forcing down to WPA1 TKIP is a solution for most users from what I can tell.  This drops you down to 802.11a/g by default in case your router does not allow for easy control of which 802.11<x> standard to use.

For others, just doing 802.a/g with WPA2 AES also works.  In my case, it does.

Anything with MCS (802.11n)  rates forces AES which seems to cause the drops. This implies it is some combination of both as the errors are AES-CCM related on my Cisco AP.

Of course we could be all facing a few different problems. However, the symptoms for most seem to be the same.  Some users fixed it by changing channels (maybe problem was congestion related), for others this did nothing.

Just sharing what worked well for me. Although not ideal, at least I can hold a stable connection.

I still believe that it is a software problem that is in Apple's hands, so I'm not making too many efforts to solve it. I continue to use Network Diagnostics, as described in my earlier post.

But I thought of sharing an interesting exprience: twice now I have moved my iMac much closer to my router for a few hours and each time the wireless problem disappeared and my connection was stable. I am wondering if the strength of the signal has something to do with the problem. It may be that the slightest weakness in the signal causes the iMac, not to disconnect from the network but to "misbehave" in the ways described above.

Anyone else tried getting the iMac closer to the router?

Btw - has anybody tried to use an external USB WLAN adapter supporting the N standard and OSX (like the Zyxel NWD2205) instead of the internal airport card to check whether the problem can be fixed?

Just wanna add mine to the list as well.  27" iMac, custom configured for the top end available.  Airport connection randomly drops out after varying periods of time, though the dropouts diminished after a PRAM reset, though resumed again over time.

From what I've seen so far, it seems like a software issue since there's no problems in bootcamp.  They used a different antenna and card design in these iMacs, so I'm betting they just need to fine-tune something and it'll work great.  At least I hope so.

You can add me to the list as well.  My 21.5" is also having wireless issues.

We have the same problem on our 27" iMac.

I'm sure someone has tried this... It just hit me when reading an article on another site.

Has anyone with the Airport problem, tried to install the 10.6.8 Combo update?

I never even thought of doing that myself. Someone mentioned that sometimes the Combo updates "fix" things that get messed up that the normal software update for whatever reason doesn't.

I am headed to bed, and going to be running a ton of video conversions overnight, or i'd just try it myself.

Just curious if anyone tried it or not.

My Airport seems to work fine 95% of the time now. every time it goes weak now (mainly after Sleep), if i just restart the iMac it seems to correct itself. Just bugs me that i DO have to restart the iMac...

I have install 10.6.8 combo update. and didnt fix anything. now i am using wired connection.

FYI i just buy iMac 21.5" 2 weeks ago.

Unfortunately, I have the exact same problem with my barely 2 months old 27" iMac... My MacBook Pro is often sitting right next to it - no internet disconnections whatsoever...