I have installed 10.5 on my G5 isight iMac and had problems from the start, freezes, choppy sound and slow boot-ups. I then re-installed with Archive and install and it ended with a kernel panic. then sometimes it would work. I would change the volume and sound would disappear. I noticed that when things worked ok the iSub wasn't playing. so I would unplug then replug the iSub to the USB port and that's when everything went nuts on the computer sound would be all choppy. I would unplug it again and sound came back on normal. I searched online and found this thread on xlr8 your Mac of someone having a similar problem. read what was Apple's reply to it... Initially, for bug # 4590777, Apple had listed it as a 'duplicate' bug, so there was some hope of having this fixed. As 10.4.4 was the initial OS X build that shipped on the first set of Intel Macs, maybe 10.4.5 would remedy this. Then the updates kept coming. And still, it wasn't working. Once 10.4.9 was released earlier this week, I tried the iSub again on all my Intel Macs. Again, no dice. So I sent in another bug report for Apple to fix. I was hoping this would be fixed prior to Leopard's launch. To my dismay, I received the following email from Apple. "Hello Anthony, This is a follow-up to Bug ID# 5061928. We have received the following update regarding this bug: <GMT14-Mar-2007 23:41:32GMT> Vanaja Pasumarthi: Engineering has provided the following feedback regarding this issue: Unfortunately, we have had to discontinue the support for iSub for built in audio. This is behaves (sic) as expected. Please disable iSub on yellow machines for all configurations. We have closed this report as resolved. Thank you for taking the time to notify us of this issue. Best Regards, Vanaja P. Apple Developer Connection Worldwide Developer Relations" This has been an issue for quite some time. As an owner of a few Intel based Macs, I'm disappointed that Apple has decided to discontinue support for their quickly emerging platform. It sort of goes against the statement from Apple that "Everything just works." Funny how the iSub does work in Windows Vista, however. Please post this for the other iSub owners who might as well know this now instead of waiting even longer. -Anthony V."