A blogger has uncovered what he claims is a "massive" bug in Apple's Mac OS X 10.5 Finder app that could result in the loss of data when folders are moved from a Mac to directly- or network-connected storage.
According to Tom Karpik, the bug manifests itself when an attempt to move - rather than copy - a folder from the Mac is interrupted. Moving a folder off a disk essentially involves first copying it then deleting the original. Karpik shows that Finder fails to ensure that the folder has been successfully written to the target disk before removing the original.
No matter what happens to the copy, the original is zapped by Finder.
We followed Karpik's instructions - albeit using a USB Flash drive rather than a folder shared on the network - and Leopard does indeed remove the original folder even though we pulled out the drive mid-way through the move.
The result: whatever data you had in the folder is gone from both the source disk and the target.
That said, this isn't the kind of problem most users will encounter. By default, Mac OS X moves files and folders when the target is the same drive as the source, but if source and destination are different, the OS copies them. To move folders, you have to hold down the Command key, and we suspect most users will copy folders and then delete the original manually.
Let's hope Apple takes note. It's already said to be readying Mac OS X 10.5.1 for release, and this should be part of the bug-fix list.
Thanks to reader Erik for the tip - and apologies for not including this line sooner