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

3days ago I started to get the same issue with my 2011 iMac 27" i7. I have been using the wi-fi for 4 weeks prior trouble free!

After a call to apple and my ISP I went into my router settings and changed the CHANNEL to 9! Apparently you can use CHANNEL 11 also.

This has fixed my issue and the wi-fi now seems to work even faster!

Btw I'm located in the UK.

I hope this works for everyone!

The saga continues and I guess I will try the channel change idea as my encryption downgrade worked for about five days and now I am back to sporadic connectivity. I can say, my temp fix (like others have stated), is to simply turn off the airport and then back on and she works like a charm till the next time it wakes from sleep.

Strangely, my problems have greatly minimized, almost to zero as well, after switching to wired for a few days, then back to wireless!

I too, did not play with encryption, channel, etc.  Just pulled the eth cable out of the back and for the last week, I've had no resets!

ideas?

Hi, i´ve like many users here experinced slow and dropping wifi connection. As I can see there seems to be an issue with how the driver/firmware for the iMac 27" (2011) in OS X 10.6.7 (All updates installed) handles WPA2 security and 802.11n?.

I´ve now configured my Cisco 1252AG (Entrprise class WiFi accesspoint) the following way to get WIFI working on a iMac 27" I7 (2011) with OS X 10.6.7.

I´ve configured the 2.4Ghz band to only support WPA Personal key (TKIP) and set it to channel 6.

The iMac now connects like it should and performance is as to be expected from a 54 Mbit  802.11g network.

Eg. 802.11n is now disabled on this interface.

Before it had support for both g and n with MCS rates up to 144Mb and the iMac world have sever performance issues and dropouts.

So in short if I revert back to WPA2 and 802.11n settings the connection will be very slow at best and there will be some connection dropouts.

NOTE! This happens when connecting the iMac 27 (2011) to both 2.4 and 5Ghz networks.

Which means it works on both bands 802.11g/a with a simple WPA personal key setup , but not with WPA2 personal key on both bands with 802.11n MCS rates support.

On Windows 7 64Bit Ultimate SP1 w/Boot Camp drivers the wireless network works flawlessly on both bands with WPA2 personal key and 802.11n rates enabled 144/300.

So the simplest solution for the wireless connection issues on the iMac 27" (2011) for me is to revert to WPA (TKIP) 802.11g only setup for the 2.4Ghz band.

And use the 5Ghz band with 802.11n support with Windows 7 until Apple fixes this issue.

For those who might or might not be interested the issue with the driver seems to behave in a way that floods the access  point with authentication data which in turn makes the access point belive its under attack.

NOTE! More research needed on this tho.

Cisco AP log.

Jun 14 18:07:07.524: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 1 AES-CCMP TSC replays

Jun 14 18:07:14.524: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 3 AES-CCMP TSC replays

Jun 14 18:07:53.524: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 1 AES-CCMP TSC replays

Jun 14 18:08:00.524: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 2 AES-CCMP TSC replays

Jun 14 18:08:07.521: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 4 AES-CCMP TSC replays

Jun 14 18:08:13.519: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 4 AES-CCMP TSC replays

Jun 14 18:08:19.519: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 3 AES-CCMP TSC replays

Jun 14 18:08:26.519: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 1 AES-CCMP TSC replays

Jun 14 18:08:34.519: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 1 AES-CCMP TSC replays

Jun 14 18:08:50.519: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 1 AES-CCMP TSC replays

Jun 14 18:09:10.517: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 5 AES-CCMP TSC replays

Jun 14 18:09:16.515: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 1 AES-CCMP TSC replays

Jun 14 18:09:22.515: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 9 AES-CCMP TSC replays

Jun 14 18:09:28.515: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 25 AES-CCMP TSC replays

Jun 14 18:09:34.515: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 10 AES-CCMP TSC replays

Jun 14 18:09:40.515: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 7 AES-CCMP TSC replays

Jun 14 18:09:46.515: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 7 AES-CCMP TSC replays

Jun 14 18:09:56.515: %DOT11-4-CCMP_REPLAY: Client <wireless card mac address> had 10 AES-CCMP TSC replays

Has the "Airport Utility" update addressed this issue? 

All it said in the info box was "bug fixes, including... " and one bug not related to this issue (quitting during setup).

Nop, I still have the same issue.

Greetings

No, this "Airport Utility" update did not fix it. This particular issue is still as worst as it was on day one.

May be this issue did not appear on the priority list of Apple yet. Too bad :-(

Same problem here.
New iMac (mid2011) and freezing connection problem...

appends randomly, now i'm running a ping every 5 sec and till "icmp_seq=508" everything ok.
I've a TP-Link router with 802n enabled...

OMG it's not just me!!!!  I have been fighting with this problem for 2 weeks and had no idea it was a problem everyone was having.  I have a 21.5" new iMac and everytime I wake it from sleep the thing crawls.  Speednet download speeds go from 30Mps down to 5 if i'm lucky.  Add to that Time Machine kicking in as well after sleep and the machine is practically useless.  I have SL up-to-date as well as the recent AirPort software update and that has not helped. 

Oh I use a 1TB TC.

APPLE HELP!!!!!

--- 192.168.1.1 ping statistics ---
157 packets transmitted, 122 packets received, 22.3% packet loss
round-trip min/avg/max/stddev = 1.222/2734.948/17924.237/4299.751 ms

This is my situation today..Avg of 2.7sec to my router...
I was on 802n, today i'm tryin with 802g ..

After a month of trying out everything that came to my mind or could be found in this - and other - thread(s) related to the WLAN connectivity issue I finally carried my iMac 12,2 back to an Apple Store to hopefully get it fixed by exchanging hardware (antennas and airport card) as Apple yet has not released a software patch.

I will report results here a week from now...

And I still would not be surprised if a driver/software update shipped with 10.6.8 or Lion would solve the issue for many or even all of us. Let's hope for the best!

Yes Kricki please let us know how the repairs go.  I'm praying that the 10.6.8 update will solve the problem.  If not I'll be packing mine up for repair as well, but it will be interesting to know if the repair fixes yours. 

Boy am I glad I'm not the only one having these issues. I thought I'd bought a dud. Same here. All devices work flawlessly on wireless and have for months. I just got Bootcamp on my iMac (had it for 3 days) and will see if the issue crops up in Windows. Will be calling apple support to add my voice as well. I may have to run a few hundred feet of wiring to my switch at this point. This is crazy. All my photos (200GB) are on my NAS and it keeps dropping on me.....

Hi all,

Thought of sharing my experience because my airport is perfectly working now. I'm not really good in technical stuff but you might want to consider following what I did. So here it goes.

1. updated my AirPort Utility (apple > software update)

2. set the service order of the network - made the AirPort first on the list (System Pref > Network)

3. followed Darkozon's solution - which is basically to re-configure the router (refer to his post above)

Note: I deleted apps like skype, firefox and yahoo messenger before doing those, but I'm not sure if that really helped

So that's all, hope that will help.

Cheers

jester

PS

I'm using iMac 3.1GHz Intel Core i5, 8G memory and D-link router

I am also having the same problem on my Mid 2011 iMac 27inch with i7 processor - if I go to System settings/Network/Assist Me/Network Diagnostics it will say my ISP has failed, but I can then reconnect to my network without problems.  Unfortunately this is very inconvenient as I am having to do it at LEAST 10 times per day and there are no problems with my 3.1 17 inch Macbook Pro (also running SL) on the same Network (although the upgrade to Snow Leopard on this did stop the DVD player from being able to burn on any media type - ironic considering I also have Window's Vista on it and the DVD burns fine through this).  In short, I have had nothing but problems since "upgrading" my Macbook Pro to Snow Leopard, and it looks like the change to a brand new computer has not been an adequate solution.