A bug has been discovered in the latest build of Apple’s Mac OS X operating system, Snow Leopard, that can erase all of a user’s data, leaving the account essentially blank.

For those of you running Snow Leopard who might be legitimately concerned, you’ll be happy enough to know that the bug is relatively easily avoided. Essentially, the vast majority of users reporting mass deletion of their data have attempted to sign into the Guest Account option, at which point results vary but the reports of erased accounts are fairly pronounced.

As well you might expect, Apple has been tacit about responding to the allegations of such a serious issue, but that’s fairly unhelpful for those users who’ve lost all of their data. Moreover, the various options available that might help in case of accidental deletion, including file recovery, appear not to be too helpful in this case.

The quotes from the official Apple Discussions page are fairly cut and dry too, including a comment from a user called tcnsdca that simply reads, “I had the guest account enabled on my MBP – I accidentally clicked on that when I went to log in. It took a few minutes to log in then after I had logged out of that account and back into mine my enter home directory had been wiped. All of doc, musics, etc gone.”

Sadder still, the proceeding comment, from a user named dubaidan, reads, “tcnsdca – that is exactly what happened to me also. I thought I might have accidentally clicked the Guest Account, but I’m not so sure – I think I clicked on my own account, but it acted as though my account was a guest account.”

It’ll be interesting to see if Apple does anything at all to try to make it up to those users so negatively effected by the whole business… if only because the potential damage done by system-wide data loss is so costly. We’ll have to wait and see, but for now we’re very curious.