Currently Being ModeratedMay 12, 2011 10:06 PM (in response to Npalamidis)
Go into your system preference and click on Network then click on AirPort click on the advance button (bottom right) when the window opens make sure AirPort tab is selected then verify the check box "Remember networks this computer has joined" is checked.
Currently Being ModeratedMay 12, 2011 10:10 PM (in response to Eric Ross)
It's already like that! I believe it's a bug of Waking up the wireless Card! Because with just turning the wifi off for and then on Manually. The imac automatically detects all the networks without problem!
Thanks for your idea anyway!
Currently Being ModeratedMay 12, 2011 11:55 PM (in response to Npalamidis)
What signal strength is the iMac seeing the wireless network at ? Option click on AirPort Menu Extra and note down the RSSI value. A value between -35 and -74 is usually good. Anything lower could cause issues.
What channel is the wireless network on ?
Currently Being ModeratedMay 13, 2011 12:25 AM (in response to Npalamidis)
if possible you can try to set your airport to bridge mode, if this helps it might be a case of having 2 DHCP services available (airport + adsl modem), which does not always work flawless.
Currently Being ModeratedMay 13, 2011 8:49 PM (in response to wifiguru)
My router is 3 feet away from the iMac. At this moment the network is on channel 149 with RSSI -42 .
I'm almost 100% sure that is a wake up issue of the iMac's airport card. Because with just turning it on and off the imac connects immediately no questions asked!
Currently Being ModeratedMay 13, 2011 8:50 PM (in response to freemem)
No Just 1 router close enough to have priority and it's the only router the iMac is paired with. There are other neighbors wireless networks but I'm not connected to any of those!
Currently Being ModeratedMay 14, 2011 12:12 AM (in response to Npalamidis)
I am facing a comparable problem which is even worth. The iMac permanently drops the WLAN connection if there is no internet acitivity after approx. 30 seconds. A real nigthmare...
The router, the location or other issues in my sphere can't be the cause as I run various other Apple divices like MBP's, iPhones, iPads and an other iMac in the same environment.
If you search the forum you'll find a lot of people facing WLAN problems with the new iMac (May 2011 refreshment).
It looks as if we are facing a serious bug with the new iMac...
Currently Being ModeratedMay 14, 2011 5:48 PM (in response to Kricki)
hopefully they correct this wireless bug soon! I'm sure we'll see a driver upgrade soon!
Currently Being ModeratedMay 15, 2011 8:59 AM (in response to Npalamidis)
finally I solved the problem by changing the channel in my router manually - that's all!
I would never have considered so because my iMac late 2007 which was replaced by the new iMac worked at the same place and with the same router without any problems.
By chance I found a general hint to do so in a forum...
However - the story remains strange and if you do not have at least a minimum of computer knowledge you are totally lost!
Hope, you get your problem solved as well!
Currently Being ModeratedMay 15, 2011 9:15 AM (in response to Kricki)
@kricki changing the channel worked for me to connect to the 5 ghz network. But I still have the wake up issue !!
The channel setup should be automatically ! That should be done automatically, just like in your previus iMac.
I hope apple is working on a Driver or Firmware update !
Currently Being ModeratedMay 20, 2011 4:20 AM (in response to Npalamidis)
+1 on the issues, using a 27" mid-2011 iMac connected to AExpress (802.11n).
Manually changed the channel, hoping for the best.
I also sent an email to apple feedback. We'll see, hopefully the update will arrive soon...
Currently Being ModeratedMay 25, 2011 9:50 AM (in response to Npalamidis)
This problem is driving me crazy! I Hope apple releases a FIX SOON!
Currently Being ModeratedMay 25, 2011 5:44 PM (in response to Npalamidis)
Same here.. every time it wakes, I have to reconnect.
My network is not public, not sure if that is related tot the issue. My old imac works fine with the same configuration as well as other wifi products....
Currently Being ModeratedMay 27, 2011 8:33 AM (in response to Npalamidis)
I have the same problem. Sometime the wi-fi connection freezes and internet doesn't work in the new iMac 21".