iMac 2011 - no wifi connection after sleep under Lion

I had the same problem with my 2011 21.5 inch iMac. The solution is to go into network settings and delete and remake the wifi connection with the minus and plus signs at the bottom. You may have to disconnect your wifi before it will let you delete it. You will also have to re-enter all of your network preferences and refind them too. also, you have to name the new one wifi. I did this and haven't had a problem in months:)

Exact same problem here.

Hi, I am responding to "A_pple"

I tried your solution but the new network I created under the name "wifi" as indicated by you, does not appear on the detected networks whereas my DSL box network, under its specific name, is still there eventhough I deleted latter via the - sign before creating the "wifi" network.

As I think of it, how could the iMac detect the "wifi" network I created as the box emits under its manufacturer's assigned name ?

I am thus still seriously stuck on that issue and my only way out is to switch off and then on, electrically, the DSL box to access anew the WiFi connection.

Just as serious, the bug can also, after a time, disconnect the Ethernet connection which I, at times, set up to alleviate the WiFi failure.

Note: Whenever the WiFi connection drops out on the iMac so does it for all my other equipments (MacBook, Mac Mini, iPad, iPhone); only the electrical restart of the DSL box will then work to reactivate the WiFi (for a time).

A terrible mess and this dating back to my installation of the Lion OS last summer of 2011..

Dream Boy i faced the exact same problem.

Every other computer in this house worked perfectly, my iMac Didnt (i mean...didnt cause now it does!!!)

SOLUTION:

Create another Internet Location using internet assitant. It will create a new Internet Settings and...somehow that solved my problem . Im using it for days, and before this i never been able to use internet wirelessly before.

Hey this seems a logical solution! Have tried it and so far no problems :) (only been 24 hours but I think this is the solution :))

Thanks for this backtothekitchen!

Others should try this solution, it can't hurt :)

For those following this thread including the Apple techs:

My continued experience despite downloading all updates to date. I have a 21.5 iMac mid 2011 model.

1. When the iMac screen goes to sleep via the settings, my iMac wifi icon stays connected.

2. When the iMac computer goes to sleep via the settings, my iMac takes a few seconds to find my wifi but does seem to connect 99% of the time.

3. When the iMac computer goes to sleep either by the power button or by using the apple icon, my iMac takes a few seconds to find my wifi but does seem to connect 99% of the time.

4. When I have to do a restart, the wifi only reconnects 50% of the time.

5. When I turn off my iMac, the wifi only reconnects 50% of the time.

Once the wifi is connected, I have never experienced a drop.

I have a basic Verizon wifi unit by Westell with number 7500. I do not believe that unit is at fault. I have a $500 cheap Dell that is 10 years old that never ever has a wifi issue. I must also include my iPhone 4S has never had a problem with connecting to the wifi.

C02HC003DHJR

like many others I am having issues with the wifi connection-

OS X 10.7.4 using airport extreme about 11feet from my new iMac, been working fine but lately has wi-fi dropout, seems to have starrted after a update recently but can't be sure.

I've tried all the fixes like deleting keychains etc posted on this and other sites, it's not happening on my iPhone or iPad or macbook with Snow Leopard when the iMac Lion OS drops out.

So its an issue with the iMac itself, be it hardware or software.

I have to turn off & on the wi-fi to restart it.

This is happening daily multiple times but only on the iMac with Lion running.

Do you have any other suggestions or can you confirm you are looking into this problem.

Regards

Jon Paske

I have suggested this several times before.

In system preferences, , energy saver, move computer sleep to NEVER.

Select display sleep to your choice- say 10 minutes

Don't like this solution? Do it anyway while you wait for Apple to fix it.

Unfortunately in my case the wifi is ok after sleep. It just drops randomly when in use. Really only seems to have started after the last update or so. I has been fine since I bought it and then problem appears all of a sudden.

Definetly nothing in way of modem, its only feet away, and iphone wifi works fine when imac drops out.

Something in a recent update has triggered this I'm guessing, but what the frack do I know.

That`s what happened with me. I`m starting to think it might be a problem with Wireless Router.

I used for 2 days a different router and things were fine. But its that. Frequent Random Drop outs. Suddenly , and without a reason .

This is driving me nuts, its so random, 2 times in 2minutes and once an hour earlier, even happens when I'm using the computer watchung a youtube clip.

Fix this !

The disconnect from internet issue is a big issue. But on my computer I don't have to reboot the machine, I just run the Network Diagnostics wizard. After selecting my wifi network in the wizard the connection is restored pretty quickly.

The following isn't a fix but has helped me. I downloaded the Caffeine App from the Apple store - "Prevent your Mac from going to sleep and displaying the screen saver." So at least if I leave my desk for a while I don't loose Internet connection. So I only have to reconnect in the morning...🙂

P.S. this is my first ever post.....

If anyone is still having problems I found this on apple support and it seemed to work for me:

Symptom: After restarting or waking from sleep, my computer might not connect to the Internet

• After waking from sleep or starting up, your computer may not show that it is connected to a Wi-Fi network.
• After start or wake, your computer may indicate that it is connected to a network, but does not connect to the Internet.

SolutionUse these steps if your computer does not automatically connect to your desired Wi-Fi network.1. Check your TCP/IP settings in the Network pane of the System Preferences. Click the "Renew DHCP lease" button

1. Choose System Preferences from the Apple menu.
2. Choose Network from the View menu.
3. Select Wi-Fi, then click the Advanced button in the lower-left hand corner of the screen.
4. Click the TCP/IP tab from the top of the screen.
5. Click the "Renew DHCP lease" button.

2. Select the Wi-Fi tab and view your Preferred Networks list.

1. Select each network and click the minus ➖ sign to remove those networks from your Preferred Networks list.
2. Click OK and close the Network preferences.

3. Remove your stored network passwords using the Keychain Access Utility.

1. Open Keychain Access from /Applications/Utilities. Your window will look like this:
   
2. Remove your AirPort network passwords from the login keychain: Select the "login" keychain from the Keychain sidebar. Click the "Kind" column to order the list of keychain items by their type. Remove all entries of the kind: "AirPort network password".
3. Remove your AirPort network passwords from the System keychain: Select the "System" keychain from the Keychain sidebar. Click the "Kind" column to order the list of keychain items by their type. Remove all entries of the kind: "AirPort network password".
   Note: The above steps will remove your Wi-Fi network passwords. If you do not know them, or if your network does not use passwords to restrict access, you should contact your network administrator.

4. Restart your computer.

5. Join your Wi-Fi network. You will need to enter your password for your network again if it requires one.

Very thorough information thanks Luke, sadly all those things and others I have found online don't seem to help in my case.

My wi-fi drops randomly, it is fine on wake up. The problem has appeared after some months of use on this new iMac with no problem. I can't remember exactly when it started but might have been after AirPort Utility 6.1 update.

Happened a few times yesterday but not at all today. Usually it is a daily problem, why not today, only the binary gods no the answer to that one.

http://reviews.cnet.com/8301-13727_7-20095988-263/fix-wi-fi-autoconnect-problems -in-lion/?tag=mncol;title

Just wanted to mention that step 3 above -- removing the Airport preferences from the root Library -- worked like a charm. I've been living with "hunting" wifi for some time and it's great to be able to open my computer and just work again.

THIS will not screw up your computer nor lose your passwords. Some other "pruning" activities mentioned in this thread may.