WiFi doesn't restore like it used to after sleep

It's late April 2012 and I am having the same problem. After sleeping, my iMac tells me that I do not have an Internet connection. I have to go through a reset where I get a message telling me that the network has reconfigured. It doesn't take long but it's a pain in the neck. No problem with wifi on my iPhone 4 or iPad 2. Only my iMac. Just installed the supposed "fix" from February 2012. No luck. If the iMac sleeps for several minutes, I still am without an Internet connection when I wake it up.

I did notice that the February fix indicated the download size to be over 25 mg. The completed download was only 1.9 mg. Fellow iMac users, what's been your experience? Thanks.

This is a continuation of my last post (Journeyman830, April 25 2012 2:28 PM). I noticed that when I checked my wifi channel, it was "149,1." Other wifi systems within range all broadcast over one channel (e.g., 1, 6, or 11). Is "149,1" a legitimate channel? Again, I'm looking for anyting that might explain why I lose my Internet connection when my iMac awakens from sleep. Thanks again.

Any solution after all these months? I am having the same problem.

When I did the download in February, it was 27.1MB. It's been working fine since then. I do notice I sometimes (10% of the time) have to wait a couple of seconds for it to wake up.

Thanks for the reply. I can't figure out why the download is described as being 27.1 MB, yet when I click download, it reads 1.9MB. Apple phone support walked me through the download and said that I should bring my iMac to the store if the problem continues. I would rather not do that if I can avoid it, especially because so many iMac wifi users seem to be having asimilar problems. If you learn anything more, please post it. Thanks again.

Enough is enough. Apple fix my darn software. IPhone and Ipads wok ok. Since the last upgrade of Lion my wireless is broke. Will not connect auomatically and will not reconnect after sleep. Such a little thing is such a big problem.

Apple told me the fix was in the next release of Lion updates. Thy are gettng a little laid back after Jobs left.

I bought my iMac in the middle of February this year and, as my first Apple, I was well pleased. Then I noticed the 'sleep' WiFi issue. However, very soon afterwards (February 25th) the 'fix' became available. I downloaded it and all was cured. No problems since, and I am running Time Machine which some earlier blogs thought was part of the issue. It seems that it works for some (most?) but not for all.

The software update fixed it for me, after I did a SMC reset.

Thanks to Gordon and Daniel for the quick replies. Daniel, I have two questions. First, what was the size of the actual downloaded update? Second, I'm not certain how to do an SMC reset. Is it easy to explain or should I go online for instructions?

Thanks.

SMC reset: http://support.apple.com/kb/HT3964

Hello. I had the same problem after I upgraded to Lion 10.7.3. Finally found a workaround that seems to help. Go to Preferences-> Network-> WiFi-> Advanced. Select all the Preferred Networks, and delete them all using the 'minus' sign under the text box. Then add just the one you know works (your local router). Save everything and shut down. It'll work after that.

Yes, it is a pain to have to manually log on to a WiFi hub later on when you are travelling, but this works well for those of us who are just using iMacs. (So far- 2 weeks.)

Guys,

I just open a case with Apple Support reporting the same issue. I bought an iMac i7 last week and upgraded with Mounten Lion (10.8) and since then every time it goes in sleep mode my wifi connection gets diconnected and it does not come up after you awake the system.

I tested the same issue with my Mac Book Pro (from Lion to Mounten Lion) and same behaviour occurred.

My other iMac and Mac Book still running on 10.6.8 doesn't have this behaviour.

Apple support already advised me to remove any all the Airport network password from the key chain, remove the system configuration from the Library preference folder but WIFI still getsdisconnected after the system goes in sleep mode.

Reading previous comments, this issue is occurring since 2011 and in some comments states the Apple will come soon with a software update solution.

Apple Support, give us a rapid solution.

Thanks

I had this same problem 10.8, my fix turn off wifi

In finder click on Go menu and hold down the option key, this will then show Library.

GO: library/preferences/com.apple.airport.airportutility.plist

delete this .plist file

switch on wifi select network, now works OK