Please advise - Corrupted image files (RAW CR2) upon transfer from the SD Card to the HDD

[asiniv]

Hi,

For quite some time by now, I've been experiencing a very weird and annoying problem, which I hope someone at this wonderful community will be able to help me resolve:

I have a Canon 60D with a few Kingston SD Cards.
I use a Sandisk imagemate SDDR-199 in order to transfer the images to the HDD.
In my own personal workflow I also convert the CR2 to DNG (loss-less), in order to save some space on the HDD.
Now, on about ~1% of the photos, the below happens:
https/goo.gl/photos/WGtcT6hUm2boDGDp9
[exported for web]

It happens at the CR2 level already, on the HDD (not on the SD, which is viewed and accessed via the SDDR-199).

So my suspicion is that some kind of a corruption happens during the transfer process,
but I just can't seem to be able to figure it out.

May someone please help me out here and explain to me why this happens and how do I stop it from happening again?

Thank you!

Assaf

 

[basroil]

It's perfectly possible that the issue is actually an SD one, especially if that happens on one or two cards only. Access patterns are different between viewing and transferring, so it's possible that the file gets corrupted by that.

Try these two:
1) Connect your camera to the computer and transfer the broken files that way
2) Use 7zip (newest version only) or another CRC32/MD5 calculator and check both files, the one still on the SD and the one on the computer. If both match, the file is broken from the get-go.
3) Open the file with your editor on the SD itself, and again using 1) . If it corrupts both times you need to buy real SD cards from Sandisk or Lexar, decent ones are only $10

 

[asiniv]

Hi, thank you for your advise.

Well, it's even weirder than I've thought:
After isolating all the files which had the problem, I've re-read them again on the SD-card itself with the same configuration I've described - They are in order.
So then I just copy-pasted them again (and only them, not the entire ~200 photos from this session), and now they "came out" just fine!
I've tried that a few more times and basically I get the same result.

So with that information in mind, I reckon it refutes your theory.
Moreover the SD card I'm using is a genuine Kingston XC 120 GB - definitely not an SD card problem.

Be it so - what do you think?

Thanks in advance!

 

[asiniv]

It's perfectly possible that the issue is actually an SD one, especially if that happens on one or two cards only. Access patterns are different between viewing and transferring, so it's possible that the file gets corrupted by that.

Try these two:
1) Connect your camera to the computer and transfer the broken files that way
2) Use 7zip (newest version only) or another CRC32/MD5 calculator and check both files, the one still on the SD and the one on the computer. If both match, the file is broken from the get-go.
3) Open the file with your editor on the SD itself, and again using 1) . If it corrupts both times you need to buy real SD cards from Sandisk or Lexar, decent ones are only $10

Hello again,
During the time that have passed, I have made further tests (on top of my last post), specifically as you've advised,
As follows:
a. An original corrupted CR2 image file: IMG_4881.CR2
b. 7-zip (latest build - 15.14):
SD CRC32: size 21957648 bytes CRC32: 6950EDEF
7-zip PrtSc
HDD CRC32: size 21957648 bytes CRC32: 2786C016
7-zip PrtSc

As you may see - the checksums differ - which leads me to believe that somehow some errors during the transfer occur.
As stated previously -
1. If I copy-paste the single image file again, it's copied from the SD card in order, without any corruptions.
2. This seems to happen only when I transfer a bulk-load of images, and only on a minute number of files from that stash.

For your convenience - summary of interfaces used:
A. Kingston XC 120 GB
B. Sandisk imagemate SDDR-199
C. Seagate FreeAgent GO 500 GB (in good health) / HITACHI 150 GB HTS722016K9SA00 (in good health, seldom used in bulk transfers due to available space limitation).

Honestly, I'm quite bewildered by this quirk
Any ideas / advice / suggestion etc. will be of great service

Thank you!

 

[basroil]

As you may see - the checksums differ - which leads me to believe that somehow some errors during the transfer occur.
As stated previously -
1. If I copy-paste the single image file again, it's copied from the SD card in order, without any corruptions.
2. This seems to happen only when I transfer a bulk-load of images, and only on a minute number of files from that stash.

Rather than a transfer issue that sounds a hell of a lot like a broken HDD...

Did you try using the camera like I said? If the camera also has issues, then try copying a folder with good CR2 files into another location on the drive that has issues. If that also has problems, you need a new HDD before more files get corrupted.