I'm experiencing a problem on my Al iMac at OS X shutdown time. Leopard was installed with an "archive and install" from the CPU drop-in DVD over the top of a Tiger 10.4.10 install on the new Al iMac. Settings and applications were migrated from a Leopard based early 2006 iMac using the Migration Assistant. At some point I've started to experience a shutdown problem. I'll shut down the system and the shutdown appears to proceed normally, including the Finder terminating. After I have a "clean" desktop (that is, desktop pictures ONLY), I'll get the "one-second" throbber that remains on-screen indefinitely. This will happen whether or not I shut down using the power button or initiate the shutdown from the menu. Does anyone have any idea how I might approach troubleshooting this issue? I really don't have any idea where to begin. Thanks in advance!