This has happened to me a few time and I'd like to know if others are having the same problem: Background: MBP 17", 4gb ram, lots of disk space, OSX 10.5.6, all apps located on system disk drive. Problem: every so often, a random icon will just disappear from the Dock. Today it was Firefox, about a month ago it was iTunes. I can add them back, but why do they leave in the 1st place. Hints or suggestions or explanations are appreciated.