I've tried reinstalling iTunes, deleting the iTunes the folder in Music, signing in and out on the store, different user and nothing works, I've also upgraded to 7.3 but no go. iTunes doesn't let me authorize my computer, I already authorized my laptop running windows and iTunes 7.3 to see if it was an Apple store problem but the laptop got authorized just fine. I'm getting really extremely mad at it and I've even thought of installing windows on it. Has anyone else run into this problem? Please help! none of my purchased music synchronizes to my iPod.

I am having the exact same problem. What version of OS X are you running? This problem began for me after I attempted an upgrade to 10.4.10.

I have 10.4.9, I used the uphuck dvd. I haven't tried to upgrade to 10.4.10, I had 10.4.8 before, and iTunes worked great on that. I've also noticed that for some reason the system all of a sudden slows down and all the programs stop responding.

I had this problem after installing Forcedeth.kext for ethernet. I had to go to /Library/Preferences/SystemConfiguration and open up NetworkInterfaces.plist. Change it so that your ethernet is en0 and your airport wireless is en1. Save it and reboot. See if that fixes the problem.

If that doesn't work, just delete NetworkInterfaces.plist and reboot. After you reboot, go to the Network pane in System Preferences and it will say it found a new network interface. Click apply and wait a few seconds. You should be good to go.

That worked!!!!!!!!!! It was a bit tricky, it kept setting itself back to en2 but I figured it out you're supposed to change IOInterfaceUnit as well not just the part that saiys en0. Thanks a lot.

Colonel's method worked for me as well. Thanks for the assist.

Hello,

I'm having exactly the same issues, but I don't really know what I'm supposed to change after opening the plist up... I'm using a broadcom gigabit ethernet card on my pci bus for my connection and I have no idea what to change... It was working up until recently, seemed to go titsup when I upgraded iTunes :-(

any ideas...

thanks

Rick

I had the same problem, made a backup of my plist file and changed the Physical NIC to en0 and the wireless to en1 and Itunes authorized my machine perfectly...

Just thought I'd let people know if they have the issue after upgrading to itunes 7+