A new problem involving serious data loss after Snow Leopard install has emerged. Some users are reporting here and here that the system has deleted their home directories after logging in to the guest account. Without backup this is a disastrous situation.

"We are aware of the issue which occurs only in extremely rare cases and we are working on a fix," an Apple representative said in a prepared statement delivered to CNET.

If you have installed Snow Leopard we strongly recommend that you disable the guest login until further notice.