Corrupt thumbs

<p>I shoot in RAW, import into LightRoom, then export what I want to keep after adjustments into my main collection. My main collection is just over 60,000 jpegs and about every month I do a full rotating backup by deleting my oldest backup and copying my full main collection. I have 4 backups of various ages going at the moment. I use ACDSee as my main viewer. OK, enough with the background.</p>

<p>I was looking through my collection last night and came across what appears to be corrupt files or at least corrupt thumbs. I viewed the full images and they worked fine. I opened these thumbs in windows and the thumbs are fine. Yet whenever I view these thumbs in ACDSee they are currupt. I looked at the same thumbs in my most recent backup and they view fine in ACDSee. </p>

<p>As far as these two thumbs are concerned I can just take my backup photos and replace them. However the whole thing has me a bit worried. I have thousands of hours in my photo collection which includes every photo I have ever taken, film and digital, and every photo my parents (long since passed) ever took. The collection is too large to look for corrupt files.</p>

<p>How can this happen? What does it mean that the thumb can be viewed in windows properly but not in ACDSee? Is there a way to have a program such as ACDSee check the integrity of my photos automatically? Should I have a different backup system?</p>

<p>Not that it matters but the photos in question are about 18 months old shot with a D700, and they are photos of old photos.</p>

<p>Corrupt thumbs from my main collection:</p><div></div>

<p>Good thumbs from my most recent backup:</p><div></div>

<p>Good argument for backups.<br>

Long ago I had a similar issue in Bridge™, but I just replaced the individual corrupted files and have had no problem since. Have no idea what caused it.</p>

<p>Digital rot? Probably not, most likely some interference with the writing-to-disk process?</p>

<p>Be useful to know, are the thumbs the issue or the JPEGs? </p>

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<p>most likely some interference with the writing-to-disk process?</p>

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<p>As the corrupted ones are part of my main collection they would have only been written once. They must have been ok a month ago when I made my last backup. I wonder if it could be an indication that the HDD that my main collection is one might be getting old.</p>

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<p>are the thumbs the issue or the JPEGs?</p>

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<p>Well the jpeg`s work fine. I always assumed that thumbs within windows or within a viewer are just miniture renders of the actual jpeg but perhaps I am wrong. I have built many websites and know of course that thumbs on a website are typically just small versions of a larger version.</p>

<p>That the JPEG's are good is good news! That indicates the issue is whatever that product uses to store previews. I'm not familiar with the product or how this is conducted. If this were say Lightroom, I'd re-import the images again, maybe delete the preference file, try rebuilding the previews etc. Again, it's good that the JPEG's are fine as if not, I suspect the thumbnails might show the same appearing corruption as the image file itself. At this point it might be useful to contact the manufacturer and ask them about this. </p>

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<p>it might be useful to contact the manufacturer and ask them about this.</p>

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<p>That was going to be my suggestion. I stopped using ACDSee some time ago because they weren't supporting my Nikon scanner 'NEF's but I did like the programme. They responded promptly to my questions and would likely have the answers.</p>

<p>Last time I saw thumbs like that was when my harddrive had a problem, in my case the originals were affected too. It can be just a glitch or a serious problem, like an indication of coming HDD failure. Check your system/HDD.</p>

<p>To check your disk for errors, run CHKDSK. Open Windows Explorer. Right Click on the disk and select PROPERTIES > TOOLS and click on Check Now under the Check For Errors section. Check the box to check for and recover bad sectors. If CHKDSK runs clean, your disk is probably good; if it does not, replace your disk and restore your backups.</p>

<p>Have you tried updating your ACDC database? That usually corrects any problems that might be there. Tools/database/optimize database. I't'll take some time but always worth doing.</p>

<p>Thank you for all your suggestions. Brooks and Don, I`ll do your suggestions right now, although Don I guess I won`t know if your suggestion works because I have already replaced the two photos.</p>