Mac OS Phanter, Tiger, Leopard Bug Leads To Massive Data Loss

A rather significant and disturbing bug has been uncovered by one Tom Karpik dealing with how Apple's OSX operating system handles file moves. Mr. Karpik details the process on his webpage, gives exact steps to reproduce the bug, and offers a downloadable video of it in action.



The bug dating back to OS X 10.3 is caused by a lack of error trapping in the "file move" process, and only occurs when moving a file or directory to another volume.

The logical file move process is a three-part procedure:

1. Copy the file from SOURCE to DESTINATION.
2. Determine if the file copied successfully to DESTINATION.
3. If the file copied successfully, delete it from SOURCE.

Apparently, Apple forgot the bolded section of Step 3, because as Mr. Karpik shows in a series of screenshots, dropping the connection to the destination -- be it a USB drive being accidentally unplugged, the power cord to a FireWire hard drive being pulled out by an overzealous feline, or a network connection to a Samba share being lost -- causes OSX to abort the copy with a "typically useful error message" and then delete the source files.

With Apple having just shipped over two million copies of Leopard, that's a lot of potential data waiting to go missing. With luck, the Update Manager will be bouncing in Docks worldwide soon.

Incredibly, a similar bug was documented in Windows Vista last month.