I upgraded my OS to 10.5.6 the day after it was released... The problem I'm having is that my Mail application doesn't make any sound when I receive an email... I checked in Preferences and the "Play sounds" box is checked... I also checked in System Preferences-->Sound-->the box "Play user interface sound effects" and all the other are checked... is someone else also having this problem after upgrading to 10.5.6 and does somebody know how to fix it?? The computer I'm using is a MacBook Pro early 2008! Thank you!