Corrupt raw files on Drobo 5c

[MarkBGardner]

I use a relatively new Drobo 5c as an archival disk, with tens of thousands of Canon raw files up to 13 years old.  A noticeable number of these files are corrupt.  When opened in photoshop, a portion or all of the photo  is replaced by a white with colored, horizontal lines.  This has not been a problem until a client wanted an image of someone who just passed away.  And that file is corrupt or unusable.  Is there a way to recover the file, and is there a way to prevent this?  Thanks!

[Terri_Stevens]

I don't know very much about the Drobo 5C except it is an network storage device. Normally these devices are fine for storage but too slow for the production environment with Photoshop. So the question is 'what happens when you copy a raw file from the NAS to your local hard drive'? Lines in raw images are often associated with GPU issues and so you could try disabling the GPU in your preferences.

Terri

[MarkBGardner]

Thanks for the suggestions.  Actually, the Drobo 5C is attached via USB 3.0 and is not NAS.  I use it as an archival disk, not for production.  Unfortunately, same result when I copied to my production (internal) hard drive.  And I tried disabling the GPU.  No change.

[Semaphoric]

Were the files okay when you initially transferred them to the Drobo?. Do you possibly have the original copy around somewhere?

Have you tried opening them in Canon Digital Photo Professional?

[MarkBGardner]

Yes, they were ok when initially transferred, and for a while afterwards when I went back to work on them for the client.  Unfortunately, I do not have the original file.

I did open in Canon Digital Photo as you suggested.  The image is rendered differently than in Photoshop.  More color, a bit more of the image showing through, but unusable. 

[D Fosse]

A corrupt raw file won't show up as corrupt until you actually open it in a raw processor. File browsers (like Bridge) or image viewers will only show you a jpeg preview, either the one embedded by the camera, or they make their own and store for future use in a cache. This preview is often fine even if the raw data are later damaged.

[MarkBGardner]

The file shows the same regardless of how I view it - raw processor, lightroom, bridge, or explorer.  All previews look fine at first, probably using the embedded jpg, then change to the corrupted version as the new preview is rendered. 

[Terri_Stevens]

what is the model of your Canon camera? What version of Photoshop are you using and what version of ACR(Adobe Camera Raw)? If you take a new photograph with the camera and use a card reader are the artefacts still there?

Terri

[MarkBGardner]

This particular image file came from a 7D.  But I have files with similar corruption that came from various 5Ds, and a 7D mk2.  Latest version of Photoshop CC and ACR.  The only time I see the artefacts are on files that have been archived to my Drobo 5c.  I never see them on my working files that are stored on my internal hard drives.  I generally archive files, both client and personal, after about two years.

[Terri_Stevens]

sounds as if there is something incompatible about the Drobo., Maybe the Drobe has a technical fault or configuration issue as locally there is no problem when saving.. I would guess if you uploaded to some Cloud Storage you wouldn't see the problem. Probably best to contact Drobo about this as they may be aware of an issue.-it might even amount to a firmware fix,.

Terri

[Anthony C Holmes]

I have also seen this problem when using Lightroom (and possibly Photoshop) using a Drobo 5N with Dual Disk redundancy connected via Wifi with my Lightroom Catalog running off local disk. The corrupted files are Canon Raws. The matching JPG is normally not corrupt (possibly never). The images appear corrupt in other (non-Adobe) programs. Sometimes if I am able to copy the "corrupt" file to another disk and back to the Drobo, the corruption disappears.

Producing a higher recovery rate: I used Chronosync to archive all my images to a portable hard drive and then restored them back to the Drobo and, as far as I can tell, ALL the corruption was cured. (But the problem still spontaneously happens while I use Lightroom.) Sometimes a Chronosync backup had to be run more than once to copy all images. (Some files produced errors or were skipped with a first run and successfully copied with a second run.)

I'm somewhat uncomfortable with my findings, as it doesn't match how I expect disks and software to fail/recover. But it offers some possibility that your (apparently corrupt) images aren't lost.