copying folder of photos from SD card = some corrupt photos, but copying those exact photos one by one = no corruption

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Level 1

8 points

copying folder of photos from SD card = some corrupt photos, but copying those exact photos one by one = no corruption

Hi All,

Can anyone think of a reason that copying a folder (in the Finder) containing 529 images from an SD card to computer would result in several of those images being corrupt, but if I copy those particular images from the SD card one at a time, they all copy ok (no corruption).

It's almost always the same images every time I've done a test copy (10 times now). Each test copy, the files that are corrupt differs by a few images (sometimes it's 10 images, sometimes 12, sometimes 15), but certain images are always corrupt.

I have tested the problem with different card readers, different cables, and copying the files to different disks (internal SSD, external USB-C m.2 SSD, external USB-A HD). I've even run Disk First Aid on the SD card, no problems indicated. I've been using these card readers for a few years, with zero problems of this type.

Since the files on the SD card are all ok, I have to conclude that there is something wrong somewhere in the chain of the copying process.

It's driving me a bit crazy, and I'm worried. I'm a pro timelapse photographer, and if even a single image in a timelapse is missing, that means that the entire sequence is not usable. Luckily, the images I'm trying to copy now weren't shot for a client, but the timelapse did take me 20 hours to shoot, and I don't want to lose it (nor do I want to lose any future work).

Any ideas?

Computer is an M1 Mac Mini, running OSX Big Sur 11.6.1, the files are raws from a Sony A7III.

Many thanks in advance for any assistance.

Chas

Mac mini 2018 or later

Posted on Mar 27, 2022 6:25 PM

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Answer 1

steve626

Level 6

13,791 points

Mar 27, 2022 9:07 PM in response to chasg

My daughter runs a photography business, so I understand the importance of what you are posting about.

The common factor for all the different things you have tried is ... the SD card itself. (Unless you can try this with another Mac.)

These SD cards can be flawed (a small percentage are defective) and all have a limited lifespan. If this is the only card with this issue, just discard it. Or, if you don't mind taking a chance, reformat it (on the camera) after copying everything safely. Test it again.

Noting also, you should update your Big Sur to the latest version to see if that helps.

If you see this with multiple SD cards, that might be a different situation.

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Answer 2

chasg Author

Level 1

8 points

Mar 28, 2022 6:12 AM in response to steve626

Hi Steve,

All good advice, and I appreciate the time you've taken to help me.

Just fyi: I'm a professional photographer with 15 years experience, and I've had a few cards go bad in my time :-) Usually failing cards show their problems in the actual files themselves (random lines showing up, or entire areas of photos blocked out with random coloured noise), but I suppose that it's possible that only the components involved in the reading process could be the problem. I've been reading the SD card Wikipedia entry, and there is a controller on the card that might have gone bad. But it's a very simple controller, I haven't read anything that indicates it acts differently when copying one file at a time, and when copying a block of files (but I'm no expert, and wikipedia isn't exactly a technical manual :-)

Once I manage to copy all of these files safely (going to be a pain to do it one by one, there are over 3500 shots in multiple timelapse sequences on this card) I'm going to run it through some stress-testing software. I usually use this software every time I purchase a new card, mainly to make sure that new cards aren't fakes (I've found a few), but it's also good to check older cards for failures too.

And you're right: I haven't removed my Mini as a variable, trying on another Mac is an obvious next step. I have some old ones gathering dust in a corner of the studio, I'll see if I can boot one up and see what happens. I'll admit to not wanting to consider my newer computer to be a factor in this problem!

As for updating the OS, that is also very good advice. I've been waiting for Monterey to move into higher numbers before I upgraded and, since it's at 12.3, it's just about time.

Many thanks again, and wish me luck!

Chas

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copying folder of photos from SD card = some corrupt photos, but copying those exact photos one by one = no corruption

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