Serious Flaw in macOS May Cause Data Loss on APFS-Formatted Disk Images [Video]

Serious Flaw in macOS May Cause Data Loss on APFS-Formatted Disk Images [Video]

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Mike Bombich, the developer of the popular Carbon Copy Cloner application, has discovered a serious flaw in macOS that may cause data loss on APFS-formatted disk images.

Earlier this week I noticed that an APFS-formatted sparsebundle disk image volume showed ample free space, despite that the underlying disk was completely full. Curious, I copied a video file to the disk image volume to see what would happen. The whole file copied without error! I opened the file, verified that the video played back start to finish, checksummed the file – as far as I could tell, the file was intact and whole on the disk image. When I unmounted and remounted the disk image, however, the video was corrupted. If you've ever lost data, you know the kick-in-the-gut feeling that would have ensued. Thankfully, I was just running some tests and the file that disappeared was just test data. Taking a closer look, I discovered two bugs in macOS's "diskimages-helper" service that lead to this result.

As demonstrated in the video below, Bombich found that an APFS volume's free space doesn't reflect a smaller amount of free space on the underlying disk and that the diskimages-helper application doesn't report errors when write requests fail to grow the disk image.

The two issues have been reported to Apple. Until the problems are resolved, CCC has dropped support for APFS-formatted disk images.

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D4xM4Nx - February 20, 2018 at 12:23pm
Thank goodness that I have backups of all the data I've got stored in my MacBook... High Sierra has been home of some of the worst bugs to plague macOS, Apple has dropped the ball like never before.
4 leaf clover
4 leaf clover - February 20, 2018 at 5:09am
Sounds like jailbreak exploit
Tmel4198 - February 20, 2018 at 3:58am
Bugs are inevitable. There will always be some. You idiots below me are the real sheeps. Sad.
Tmel4198 - February 20, 2018 at 3:58am
I find it funny you follow a blog/article app call iClarified. “i”Clarified. iPhone, iMac, iOS, = Apple
Lmao - February 20, 2018 at 3:00am
Dumb sheeps! Lol
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