repair permissions. After every software update, and about every 2 weeks: close all apps and log totally off. Log on, go in Finder, Applications. Utilities, Disk Utility. After the message -getting disk information- select volume (below the hard drive name -upper left corner). Just highlight it. Now look to the lower two things are there near the middle, verify permissions, repair permissions. Click repair permissions. Also make sure you run cron tasks Finder, Applications. Utilities Terminal type (switching to root - superuser) sudo sh /etc/daily > this needs to be done /weekly (instead of daily) and monthly. again with all apps closed. If that oesn't help - boot into single user mode (restart, hold command S after the tone. it's gonna look strange type fsck and repeat until *****FILE SYSTEM CHANGED**** stops showing