Q: 10.7.3 no wifi connection after wakeup

That's because your computer is really never going to sleep. It's just shutting down the display. The rest of the computer is still running...

I have mind checked, and mine connects very well to the home network.

I think it all depends on the hardware rev you have. Not sure what iMac you have, but it seems to affect i5 and possibly i7 iMac's.

MBP and MB, at least in my experience are not having the issue. Just my iMac i5 model ID 12,2

Unless you're putting it to sleep manually, your computer (hard disk) is probably not actually going to sleep; only the display is sleeping.  That's why this suggestion from AppleCare is just a temporary fix.  Once they get a permanent fix, you will probably want to check that box again so that your hard disk can sleep when you're not using it (saves power). 

I also tried Hydnjo's suggestion after manually putting the computer to sleep and it worked!  Only tried it once so far, but I'll keep testing it.

Hydnjo,

I've tried your suggestion of waking the computer by tapping the power button (after putting it to sleep manually) several times now and it's worked every time!  I appreciate it because I'd rather let the hard disk sleep when possible.  Thanks.

RainyWeather,

Me too! I wonder if I can go back to 10.7.2.

Don't go back yet! They're working on a fix.

I have a mid-2010 Mini Core 2 Duo, it's affecting me and my daughters 6-month old Macbook Air i5.

Cannot seem to reconnect after waking...this is a real pain since I use my mini as a media server with Plex for our tv upstairs...have to wake the mini up to enable it to connect to the tv.

I have the same problem with my iMac (mid-2011, 21.5"). Lost Wi-Fi after waking up from Sleep.

Tried following without success:

- Deleting/ Adding Wi-Fi

- Clearing PRAM (cmd+alt+P+R)

- Clearing SMC

- Reset Router (Netgear)

- Installed Combo Update (3 times)

... nothing helps. ;-(

Waking up with the Power Button is a temporary workaround.

Exactly the same with me. 2011 iMac 21.5 inch owned for 5 months - I have never had this problem before and from the minute I installed 10.7.3 the Wi Fi has not connected automatically after waking up. It's blooming annoying!!! The workaround with the power button does however appear to work.

Actually I have got two user accounts on my Mac. Mine exhibits this problem but the other account (my wife's) does not seem to. Both are administrator accounts although I loaded the update from my account rather than the other one. Not sure if this is relevant.

One more to report, 2009 iMac 27'' losing wifi after sleep. Hope at least someone comes up with some "delete preference file X" and not having to wait for 10.7.4.

I know it's been posted supposedly their working on a fix.

But in the mean time I would suggest providing feedback. Without everyone having to call into applecare this takes 5 mins, easy to do and will provide feedback to them of the exposure of the problem. Provide as much detail as you can including the exact model number. (Click the Apple in the upper left,

About this Mac, More info, System Report, Model Identifier)

Example:  Model Identifier:          MacBookPro6,2

http://www.apple.com/feedback/imac.html

First thing I did, report the bug with the feedback form. I suggest everyone to do the same

James - many thanks for this link. I was trying to report the bug but I didn't know how. Now I too have logged my feedback on there.

I may have fixed mine.  I deleted the connection and re-added it in my Network Preferences.  After being at work all night, I came in and it was still connected.