Warning: Snow Leopard Deletes All Files If You Use A Guest Account.

By Benedict Wee

Recent reports by various tech-blogs indicate that anyone who logs on to the Guest account of Snow Leopard-run computers will cause the OS to delete all user files on the main account.

If you've just upgraded your Mac and have a Guest account, I highly suggest that you disable it until the situation has blown over.

As of writing, Apple has not responded nor addressed the issue of the fatal bug.

Source:

Gizmodo - Reports: Snow Leopard Bug Eats User Accounts Whole.