For the past 2 weeks the wifi on my iMac (27in 3.4ghz i7) has constantly cut in and out after the 7.6.3 update for the Airport Extreme was installed which resulted in trouble for all devices in the house (ipad, iphones, Apple TV, mac mini, mb pro,) so I rolled it back that same day 2 weeks ago to 7.6.1 and everything has worked fine besides my imac which picks up a connection for 30 seconds and then drops out (in airport utility the internet keeps going amber/green/amber etc) Worst part about this is that right before it drops it locks up the entire network so all the other devices wifi doesn't work....so i have to shut off the wifi on the iMac to allow the devices to connect. Figured 10.8.3 may address the issue so I only used my iMac for photo editing, which is ridiculous, but I installed 10.8.3 when I saw it posted yesterday and the issue persists. I tried every damn fix I could find (returned router to factory settings, created new network, changed MTU, channel, keychain access, repaired disk permissions, etc, etc) and wasted the day and this morning ***** with this! Finally decided to create another admin account and the internet hasn't dropped for an hour....which is unreal after the hell the other account has had! Don't know what got corrupted but I've been digging in the console and see mdnsresponder messages and other crap that leads me to not even want to mess with the account anymore. I've wasted countless hours reading about possible solutions but I'm now just glad to have a Working wifi signal on my iMac. TO THE POINT: Whats the most efficient way to move stuff I've acquired over the past 10+ years of using a mac to a new admin WITHOUT bringing whatever is causing this wifi issue along?? I'm lazy and stupid so I've just migrated from a Powerbook G4 I had in 2003 to a MacBook Pro in 2007 and then ultimately to this iMac in 2011....so I know I've drug a lot of un-needed crap along in these 10 years!