As discussed in Mac Geek Gab 355, Access Control Lists (ACLs) are permissions that impact user-level access rights within OS X.  They are different from Permissions, which impact system-level rights.  In simplified terms, items inside the user’s home folder are regulated by ACLs while items outside the user’s home folder are regulated by Permissions. 

Due to this distinction, using Disk Utility to Repair Permissions will not resolve issues related to objects in the user’s home folder.  To resolve these issues, we need to “reset ACLs.”

In OS X 10.6 Snow Leopard, boot to the Mac’s install disc by inserting the disc and holding down the “C” key at startup (or holding Alt/Option and selecting the disc from the boot menu).  Once you’ve selected your language and are at the installer’s main menu, choose “Utilities” from the menu bar, then “Reset Password.”  This menu allows you to reset user account passwords but also allows you to reset ACLs by choosing a user account from the top menu and then clicking “Reset” at the bottom of the screen.

The Reset Password Menu in Snow Leopard and Lion’s Installers lets you reset your Access Control Lists 

In OS X 10.7 Lion, Apple removed the Reset Password option from the Utilities menu in the Recovery Partition.  Dwight Silverman over at the Houston Chronicle found a workaround: boot to Lion’s recovery partition by holding “Command-R” at startup (or holding Alt/Option and selecting the recovery partition from the boot menu).  Then, from the Utilities menu, choose Terminal. Type “resetpassword” into Terminal and hit Return.  This launches the Reset Password menu.  From here, proceed as you would have under Snow Leopard.

Once the process is complete, exit the utility and reboot.  This should resolve any permissions issues involving user-level objects.  Thanks, Dwight, for the great tip!