I had a nice e-mail exchange with the manufacturer of my modem/router, a FritzBox WLAN 7360, quite common here in The Netherlands. They told me that in cases like this, they advised customers to instruct their product to EXclude the use of radio channels 12/13, and to UNcheck the option to use radio channels optimized for 300 Mbit/s. I took their advice, and after searching for a solution for over a year, this finally did the trick for me. At last! WiFi between modem/router and iMac has been stable now for more than 4 days, while it dropped the connection at irregular intervals before. Problem solved, no more ethernet cable! Of course I don't know how to do this on other brands of routers, but I'm sure you will find a way. I had to go into 'Expert Mode' on the FritzBox in order to fix this. Scary, but it worked.
It is now obvious that the WLAN-card (or more likely its firmware), built into the newer iMacs, is to blame for all our anger and despair. It's really time now for Apple do something about this, or to issue general instructions how to handle this problem as a minimum.
I am too having a issue with the Mountain Lion OS and Wifi dropping out. It drops out at the most inconvienent times as well.
I do Lets Play videos regularly on Youtube, and I can be in the middle of a upload, and the wifi will simply cut out and I will have to start all over again, its just NOT acceptable Apple.
I was just watching a TV show with Quicktime on full screen, and when I came back Wifi was killed and my upload link was severed. STAHP THE MADNESS APPL!
Fix meh OS plz.
Since some days same problems here.
Using Mountain Lion (now) 10.8.2. (& TimeCapsule 7.6.3 as Router). It seems to be a ML problem since one co-worker also using ML has the same problem (repeatly dropping wifi connections), but not a SL user. As the identical symptons appear also at home it is not a problem with the wlan router (because no problems at all using iPhones and/or iPads). ML is dropping the connection (after view minutes) and fails to automatically reconnect/establish a new one. I do use ML since the very beginning, but only experience wifi-problems since a view days.
Also tried various suggestions from this posts, but to no avail.
Not shure if recent TC updates are the cause of the pains (in my case i also have a TC at home).
This is really disappointing!
For my case, I had problems with intermittent WiFi after a trip to China. Nothing mentioned in the previous replies worked for me.
But one thing fixed my problem completely. I changed my router setting from using "Mixed b/g mode" for WiFi to "g only." After that I have stable WiFi for two days till now. Don't ask me why, but try it if you haven't. Maybe it'll work for you too...
On what kind of Mac do you experience this problem?
I struggle with the same problem for over a year now, and it becomes clearer and clearer to me that this is a problem of frequencies and optimizations in WiFi-land, things a normal person does not know about. The manufacturer of my modem/router (a Fritzbox 7360, quite popular here in Europe) advised me to switch off radio channels 12 and 13, and to deactivate the channels optimized for 300Mbit/s, whatever that means, because, and I quote:
'Various WLAN devices or adapters do not handle these channels very well.'
which would mean, in our cases, that certain WiFi-cards built into our Macs are not up to their tasks. I have suspected the Atheros WiFi-card (with 4.0 firm- or software, 3.x is ok) in my mid 2011 iMac for a long time, but nobody seems to agree, certainly not Apple. They remain silent.
The manufacturer's advice certainly worked for me. No more WiFi-drops for 3 weeks now! You probably did something like this by changing from b/g to g only.
Oh yes. Since i installed 10.8.2, tried every possible tweak, read all the threads about it. It's the first time i'm actually writing about it. I had high hopes for 8.3
The best result i got was getting wifi to detect and connect effectively for a few hours at some point (maybe 1 month ago). And then it died again after.
It's of course a figure of speech that has the intent to show that for a "simple" computer user as myself, i did try a lot of things for a long time now. i'm not sure about naming each and every one of them but i'll try to list the categories:
- PRAM, SCM
- New Location, deleting known networks,reordering internet connection methods..
- Router (i do have other devices connecting perfectly to it, as was my MBP before 8.2) : changing channel, MTU, changing from WEP to WPA2, activating WPS, deactivating everything and resetting a new different SSID...
- Keychain : deleting the known and stored network lines
- Kext files : i'm not sure what i did with those
- New MBP users : created two other fresh users with different profiles...
- Hardware tests
- Going to different places with diferrent WIFI routers and settings
i do agree that this might not cover "every possible tweak", as nothing is absolute. But i'm just tired of trying.
To summarize the problem: Lion and Mountain Lion have problems recognizing Apple wireless routers.
Since 2007, I've been using an Airport Express router. Over the years, several Macs, one PC and one iPhone 3GS have been connecting to this router without any failure, each of these devices having run on various versions of its operating system.
The problem started to occur when I installed Lion. It was hard for it to see the router, while it kept finding without problems all neighbouring non-Apple routers. I often had to try several times. The problem persisted with Mountain Lion but was greatly improved with the 10.8.2 upgrade. However the 10.8.3 upgrade was a catastrophe as it just does not see my Airport Express. I then did a full reinstallation of my Mountain Lion partition but it keeps not seeing my router. Of course I tried all the recommended manipulations to try and fix it but got nothing. I'm writing this message from my Snow Leopard partition.
Fed up and on my way to a computer store to buy a new non-Apple router.