If you’ve been noticing that your iMac won’t connect to your Wi-Fi network after waking from sleep, you’re not going crazy. It’s actually a bug in 10.7.3.
But have no fear, Apple is here … with a patch for 2009 iMacs. Software update should have a nice 26 MB download that will replace your faulty Wi-Fi drivers with some new fandangled goodness. You can either check Software Update, or download the patch itself from Apple’s website.
Keep in mind that this patch is only for 2009 iMacs, and should not be installed on any other system. It’ll probably do more harm than good if you install it on any other machine.
Via: CNET
