Snow Leopard has come under some scrutiny lately for a bug which has the potential to delete user account data. The bug was first reported in Apple’s discussion boards, where more and more people started reporting the problem. Here’s a post from the discussion boards, highlighting the problem:
“I upgraded from Leopard to Snow Leopard last week. By accident I clicked on the ‘guest log-in’ icon on my MBP 30 minutes ago. After about 1 minute it automatically returned to the log-in screen, without showing up the guest desktop, so I decided to click on the ‘guest log-in’ again. This went pretty smooth and when I logged out the message appeared that all the ‘guest log-in data’ wouldn’t be saved, but returned to normal. When logging in to my regular account, everything was gone. I don’t use filevault. Nothing has been renamed to something else. My home-directory still exists under /Users/username but it is just empty.”
It appears that when users log in as guests, that there’s a chance when they log back into their regular accounts that all of the user data is missing. As of now, the only solution is to back up all of your files. If not then you could find yourself losing a massive amount of data.
One solution being presented is for users that upgraded from Leopard to Snow Leopard should disable guest accounts, then re-enable it. This creates a brand new guest account, and it has apparently been helping people with the bug.
Apple has officially addressed the bug, stating, “We are aware of the issue, which occurs only in extremely rare cases, and we are working on a fix”