I hooked up a generic USB keyboard, plugged in a wireless USB mouse, and disabled the bluetooth on the iMac. Since then, NO WiFi problems. I'm talking ZERO. Streaming music as long as I want, uninterrupted streaming movies, computer sleeps and wakes up and the WiFi reconnects instantly.
Makes sense. I think this pretty well sums up the root cause of the problem and it's something I thought of early on in this saga, especially as the imac's internal wifi card has always had problems with shielding/reception. So add in Bluetooth this and Bluetooth that and it's bound to lead to these kinds of problems. It might even be down to the distance of the keyboard from the mac or the location of the wireless router. BTW, no dual-channel available, just a Broadband co supplied Thomson router, on the floor below.
Just did the procedure recommended by McCainiac and it worked for me (at least for now, I rebooted, logged out) my MacBook Pro's WiFi connexion came back ok...
I have tried a lot if not all suggested solutions on this and other threads, this is the first one to work for me
Had been running Lion for quite a while before the problem occurred.
This is the article:
Go to bottom of page where it says:
Symptom: After restarting or waking from sleep, my computer might not connect to the Internet
iPad, MacBook with latest version 10.7.3, and dell system connect fine to wifi. IMAC has not, does not, will not stay connected. After HOURS and Days Of going through endless leads through this forum and osxdigest, Nothing works. Genius bar says that there is no problem with airport.
like many others in this forum I am really getting tired of waiting for apple to address this problem.
Anyone interested in finding a collaborative legal class action way to get apple to address this issue?
Sorry to hear this did not work for you guys,
I have been trying just about everything (that makes sense) before simply resetting the WiFi interface (en1) and removing all airport entries in the keychain as the link reference given by McCainiac suggested
My MBP has been working fine with Lion for quite a while before the problem occurred. The only thing that seemed to change in my environment (and probably triggered the issue) was the appearance of a new WiFi network (my neighbour got a new router).
Again, I did a total reset of the WiFi interface, removed everything, this would also remove .plist entries for airport (com.apple.airport.airportutility.plist) and made sure the keychain entries were deleted.
So far still working after many sleeps, re-logging, re-starts...
How are you attempting to set up your imac, through airports wireless utility accessed through your Macbook, or via the network set up of the imac itself - use the former not the latter. Make sure your imac Mac address is listed along with the mac addresses of your other mac connected devices. Put your imac top of the list.
Given your previous attempts I would also flush the following on your imac
DNS, interface parameters, TCP, and ARP. And try the following first to isolate your imac's wireless adapter as a possible fault.
Connect your imac to modem using ethernet. test your ethernet interface is working and you can obtain the internet ok
Plug the ethernet cable back into the airport from your modem.
Turn on your macbook and using an admin login, set up an adhoc network called imac test, give it a wep password.
Disconnect your Macbbok from the airport wireless, then ask it to connect to the adhoc network so it is broadcasting.
Using your wireless on your imac scan for it and see if you can connect.
If all is well. Reboot both machines, and retest the adhoc connection as before.
Remember to log in with full admin privileges on both machines whilst setting up and testing.
If you have any trouble connecting your adhoc then check for signal compatibility issues in the wireless adapter property settings on both machines, ie mode, channel, signal strengths, roaming aggressiveness etc.
If you still have problems with the adhoc - have your wirelss card changed in your imac
In writing this I have made no assessment of your networking skills, which may be vastly superior to my own, but sometimes a fresh perspective can help. This is what I would do if it were me, but its your time and your call. I am aware you might have done this adapter elimination process already, in which case sorry to have inconvenienced you with the time it took you to read this. best regards, Ct
On my MBP this issue began to occur AFTER the latest sw update on April 9th. I have been running Lion for over 2 month now with no issues. After the last sw update, the connection drops randomly but it stays connected for no more than 5 minutes at a time, making web browsing nearly impossible. I've tried the suggested creation of a new wifi area, which worked for about 15 minutes, then back to dropping.
My ISP is maintaining my router; they set it for 802.11g, not 802.11n and it now stays connected as long as the computer does not go to sleep. When it sleeps and wakes up, it is not connected, but immediately does connect. I can live with this, but it's still not right, is it?
With my setup, on 802.11n it disconnects after a couple of minutes -- not usable; on 802.11g it disconnects in sleep, but re-connects immediately upon waking.
Woodland, CA, USA