I am surprised that there is so little posted about connectivity problems on this forum. The Communities section of the Apple Support site as many threads dealing with this. I have a three-week old 17" MacBook Pro running OS 10.6.2 that frequently disconnects when inactive. I can sometimes get back on line with a Restart, but at other times it's more complicated. I've spent hours on the phone with Apple technical support and have had my Airport card replaced. Nevertheless, it continues to happen.
I'm really puzzled that this apparently doesn't afflict more MacBoook Pro users on this forum
I'm really puzzled that this apparently doesn't afflict more MacBoook Pro users on this forum