Problem on import

[Jeffrey Saldinger]

Using the same import workflow I have been using for years, over the past few days I have observed the following anomalous behavior. 

In the import interface, the images I see (i.e., I import from the card in my laptop’s card slot) are exactly the ones I expect to see.  But when the import is finished and I look at the just-imported images in the Library’s grid view, one of the images (only one; the others are fine) gives the preview of an altogether unrelated image yet it has exactly the file name I would expect for image I don’t see.

When I look at the file in the finder, the thumbnail I see there is exactly the right one I would have expected, not the one that I see in the grid view.

Before posting this, I tried creating a virtual copy of the problem file; switching it back to color (i.e., I use a BW preset upon import for everything; it remained the “wrong” image); and then exporting it to my desktop as “original.”  Once again the finder shows the proper thumbnail, but this time, when I import this file I get a fleeting view of the “wrong” thumbnail which right away switches to the proper thumbnail I was expecting from the beginning.

I also tried opening (from Lightroom) the “wrong” file in Photoshop.  It opened with the proper image and file name; when I closed it (without saving), the thumbnail (and loupe view too) reverted to the “wrong” image.  When I open the wrong file a second time and saved the PSD, I have the image I was expecting.

Perhaps I should add that the files in question are DNGs, not proprietary raw files.

It’s nice to have found a workaround for this problem that I can live with (assuming no further anomalous behavior with my workaround), but I’d like to learn something from this and will value respondents’ input about what might be going on.

[dj_paige]

Your preview cache is most likely causing this problem, and you should delete the cache and Lightroom will create a new copy that should eliminate this problem.

To do this, close Lightroom, and then using your operating system, go to the folder where your catalog is stored, and delete the folder whose name ends with Previews.LRDATA. DO NOT DELETE ANYTHING ELSE.

[Jeffrey Saldinger]

Thank you for the prompt reply. 

I'm in unfamiliar territory here.  Before I delete that folder, can you please say something about what I can expect when I resume working in Lightroom?  Will deleting this folder mean I have to recreate previews for my whole catalog?

Also, I notice that the folder you recommend deleting is about 7 GB.  How is this number related, if it is, to the Adobe Camera Raw cache section of the Preferences>File Handling panel?  It is not part of the Lightroom catalog (i.e., not on disc in the same place) and is set for a maximum size of 50 GB?

[dj_paige]

Will deleting this folder mean I have to recreate previews for my whole catalog?

No, it means that Lightroom will create the previews for your catalog. This happens automatically. You don't have to do anything.

Also, I notice that the folder you recommend deleting is about 7 GB.  How is this number related, if it is, to the Adobe Camera Raw cache section of the Preferences>File Handling panel?  It is not part of the Lightroom catalog (i.e., not on disc in the same place) and is set for a maximum size of 50 GB?

No relation at all.

[Jeffrey Saldinger]

Thank you.

Just to become familiar with this operation, I tried this with three very small Lightroom catalogs I've used for miscellaneous purposes.  It worked fine. 

But one thing I noticed was that in each case the size of the previews.lrdata cache shrank considerably, e.g. in one case from 73.6 MB (old cache) to 15.2 MB (newly-generated cache), and the ratios of before/after sizes were 4.8, 3.4, and 8.2.

I'd value whatever you might be able explain about what's happening "under the hood" to determine this disparate results.

Appreciatively,

Jeffrey

[ManiacJoe]

The files in the preview cache are created only as they are needed. If you do not view an image in Lightroom, its preview will not be created even though the file is listed in the catalog.

[Jeffrey Saldinger]

Yes, I see.  In one of the catalogs from yesterday (its new cache was 7.9MB down from 26.9MB), I looked at each image 1:1 and the cache became about 80MB.  Thanks for this greater understanding which, having read a bit about the caches, is now obvious to me.

One thing I didn't mention in my original post (because I thought it might unnecessarily complicate it) is that I observed this "cache behavior" (if that's an ok term for it) in two catalogs, one with the files and catalog on my laptop and the other with the files and catalog on an external drive, and only (in each of the three imports) with one file.

If the problem is with the cache, it seems strange that it would manifest itself almost simultaneously on two catalogs that "don't know anything about each other."

Might there be more going on here for which there's a straightforward explanation?

[dj_paige]

Happening in two different catalogs? The only explanation I can think of is that your hard drive is malfunctioning somehow. Consider replacing it. And definitely, regardless of whether you replace it or not, make sure you have current backups of your catalog file AND current backups of all of your photos.

[Jeffrey Saldinger]

Thanks.  Will continue to work on this.  Happy to say I'm diligent about backups.