Whatever happened to previews.db in Lightroom 5 Catalog Previews.lrdata?

[Judas_Gutenberg]

In earlier versions of Lightroom, there used to be a file called previews.db inside a directory called "Lightroom 5 Catalog Previews.lrdata" , but in Lightroom 5.7, I see that "Lightroom 5 Catalog Previews.lrdata" has become a file (no longer a directory) and there is no previews.db. I had a plugin that needed to read previews.db in order to generate thumbnails. Now I don't know what to do.  (Rob Cole, you wrote the function that did this, and it worked great while there was a previews.db -- perhaps you know what is up.)  If anyone can point me to where a file similar to previews.db can be found (it has to be parseable by sqlite), that would be very helpful. Thanks!

[ssprengel]

The folder containing my LR 5.7 catalog still has a (catalogname) Previews.lrdata FOLDER with a previews.db that was updated earlier TODAY the last time I was in LR.  That folder also contains a root-pixels.db which was updated yesterday, perhaps the last time I imported something, then 16 subfolders with single-hex-digits for names: 0-F.

[areohbee]

Judas Gutenberg wrote:

in Lightroom 5.7, I see that "Lightroom 5 Catalog Previews.lrdata" has become a file (no longer a directory)

Whoa - something bad happened. you best delete (or rename for now) that .lrdata file and try again.

There have been no changes to preview folders / files in Lr5.7 that I can tell.

[Judas_Gutenberg]

investigating further, i see that the "file" is actually a .zip file on a macintosh (though it does not have a .zip extension until someone tries to attach it to an email).  within that .zip file are all the ordinary catalog files, including previews.db.  does anyone know what might cause this to happen?  this particular installation of lightroom works okay with this arrangement.

[ssprengel]

I don't use a Mac, so cannot answer definitively, but perhaps this folder was compressed either via selecting some option on the folder, itself, or by running some maintenance function that automatically compressed folders that were deemed as wasting space.  I would think you'd want this to be an compressed folder so as not to use up an inorfinate amount of time to work with the previews contained inside.  Can you make an uncompressed copy and then rename the compressed original as something else and rename the copy to the correct folder name?

Here is some info on compressed folders on Macs I found by Googling:

OS X Mavericks: Compress and uncompress files and folders

[areohbee]

Confession is good for the sole.

Is there anything you'd like to tell us now Judas?

[Judas_Gutenberg]

i've been testing a plugin on a variety of setups and it appears the problem is actually coming from some other plugin that is secretly compressing the contents of the XXXX.lrdata directory, making it into an zip file and somehow cloaking the .zip extension. i've asked this tester to please try to isolate the problem but so far i haven't heard back. has anyone ever heard of this? it seems kind of shady for a plugin to take it upon itself to do such things.

[ssprengel]

I doubt a plug-in would secretly do anything, much less be able to compress a folder and hide the ZIP extension. On the other hand, a human, perhaps unknowingly, could compress a folder as shown by the link I posted, above. You’re the human at the keyboard. You’ll have to solve this one, yourself.

[Judas_Gutenberg]

technically i'm not the human at the keyboard, this is someone else's system (it's in the UK, and using remote desktop software with that kind of latency is basically impossible though i did try). initially i was perplexed by the inability to find previews.db on a computer that was successfully running lightroom, anyway, it's seeming as if the problems with this particular installation are esoteric enough for me not to have to worry about. i was just hoping someone who knew more about the range of possible lightroom setups could shed some light on this issue.

[areohbee]

Well, this is the first I've heard of such a thing - definitely something very unusual going on.. - good luck, and thanks..

[ssprengel]

The link, above, explains how to compress and uncompress a folder.  This is a Mac-OS thing, and nothing to do with Adobe or Lightroom.  Talk to the user who's system this is an ask them about it or decompress the folder yourself.