Corrupted image files

Question

Corrupted image files

Over the past year or so, I've noticed some of my image files becoming corrupted from time to time, but recently this issue has been occurring quite often, sometimes affecting a dozen files in a 300 image import.

All of my photos are referenced on an external hard drive outside my Aperture and Photos libraries. The libraries are on my Mac's internal drive, but to be fair, I have noticed this issue only in Aperture—probably because I never use Photos. The corruption does not occur during the import process because it sometimes affects files that were created (via third-party plug-ins) after the images were added to the library. In almost every case, I have been unable to restore from the Time Machine backup because the backup copy seems to have been added to the backup after the corruption occurred.

Here's an example of what I'm dealing with:

Those lines are basically the original content offset and wrapped around from the other side of the image. It would be an easy(-ish) fix if they were a straight wrap, but several of the lines are broken on the top and bottom edge, making a kind of slanted edge which is very difficult to correct with any degree of accuracy.

The above image was shot in 2013, but that TIFF conversion was performed in the last few weeks. Nevertheless, the backup copy shows the same corruption, indicating the file was corrupted before the backup was made, or the backup copy and the copy in the library have both been corrupted in the exact same way, something I find highly unlikely.

I know Aperture isn't supposed to change the original file content in any way, so I'm hesitant to blame the app. On the other hand, I was importing some images today and 10-15 of them showed this same corruption immediately after the import. Luckily, I never delete files from the memory card until I need to re-use the card, so I had the originals that I could use to replace the bad files on my external disk. Up to now, I have been using the camera's JPEG previews as Aperture's previews, but after today's fiasco I've switched off that feature and from now on Aperture will create its own previews immediately after import of every image, so I can see right away which files are okay and which ones are damaged.

Is it possible that Aperture is damaging the files in some way as it transports them from the memory card to the external hard drive? Could it be the Finder that is causing the issue? Could it be my less-than-six-month-old external hard drive that is corrupting the files as they are transferred to the disk? Is there any way for me to check these systems to find out which one is the definitive culprit? Has anyone else had this problem?

iMac, OS X Yosemite (10.10.1), 27" iMac Core i7 Quad 12GB

Posted on Sep 20, 2015 8:39 PM

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Answer 1

Best reply

léonie

Level 10

194,531 points

Sep 21, 2015 7:05 AM in response to Phillip Breske

Is it possible that Aperture is damaging the files in some way as it transports them from the memory card to the external hard drive? Could it be the Finder that is causing the issue? Could it be my less-than-six-month-old external hard drive that is corrupting the files as they are transferred to the disk? Is there any way for me to check these systems to find out which one is the definitive culprit? Has anyone else had this problem?

Over the years I've found about 200 damaged jpegs in my Aperture library of roughly 100000 photos.

In some cases I could trace the damage to be caused by the card reader or the camera, because the originals I backed up directly from the card showed the same corruption. In other cases I am pretty sure, that the damage has been caused by bad blocks on the external drive with the library. The backups of the originals were fine, as well as photos I exported from Aperture. So originally the originals have been o.k., but something modified them later in the Masters folder.

You may want to make a separate backup of your originals on the external drive, independent of the Time Machine backup. Check the drive with the originals using Disk Utility to make sure it has no issues.

I used an application "Corrupt JPEG Checker.app" to scan my drive with photo libraries. It turned up a frightening amount of corrupted JPEGs, but I could restore them from the backup of the originals that I made direcly before importing to Aperture.

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Answer 2

Sep 21, 2015 7:04 AM in response to léonie

That's a good idea and something I'll start doing myself. I'll create a new "Imports" folder and copy all my camera files directly to that folder, then use Aperture to import copies from that folder to the referenced folders on the external hard drive. That way I'll still have the originals on the memory card (for a while) and in the Imports folder for at least a few backup iterations to make sure none of the imported versions are damaged.

Thanks!

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