Lightroom Classic CC 7.3: Unchecking "Generate Previews in parallel" doesn't seem to work

  • 1
  • Problem
  • Updated 7 months ago
  • (Edited)
I thought I would understand how this option works. There is a newish feature in Lightroom that generates the previews while the import operation is still occurring, and not just an operation that's in the action queue to start taking place after all the importing is finished (as how it used to be). I saw this become an option after the feature was added, so I assumed unchecking the checked option (which is checked by default) would make previews stop generating alongside the import. But it seems to do nothing.

Screenshot shows the option as unchecked, but there are still two operations in the top left corner (importing and rendering). Option was unchecked before I created this catalog.



Can someone correct me if I'm understanding this option wrong? I've googled but found nobody else seeming to experience this problem. I'd assume that the description for the option is straightforward, but it seems to be useless..?

Lightroom Classic CC 7.3 on Windows 10. Had the same issue on 7.2 on Windows 7 as well.
Photo of Andy Hasak

Andy Hasak

  • 13 Posts
  • 8 Reply Likes

Posted 7 months ago

  • 1
Photo of SatishT

SatishT, Employee

  • 68 Posts
  • 24 Reply Likes
Hi Andy,

This option flips the behaviour of preview generation between sequential and parallel preview generation.
If this option is checked, Lr will generate previews in parallel(i.e more previews per unit of time, reducing overall preview generation) otherwise the previews will be generated sequentially.
This option will not affect preview generation happening in concurrency with import i.e Lr will generate previews while importing the photos irrespective of the state of this option.

HTH, Satish
Photo of Andy Hasak

Andy Hasak

  • 13 Posts
  • 8 Reply Likes
Okay, I think I understand it better now. Rather than the previews being generated in parallel to the import, they're being generated in parallel to each other. Thanks for clearing this up, although I would like an option to do it the old way, i.e. enabling previews being generated automatically after the full import is done (rather than after each smaller batch during the import). The new way is probably a faster result overall, but uses a lot of resources when I could be doing other work on that HDD as well.
Photo of Johan Elzenga

Johan Elzenga, Champion

  • 1541 Posts
  • 622 Reply Likes
If you do not want to generate previews during import, then use 'Embedded & Sidecar' during import. You could also disable Preferences - General - 'Replace embedded previews with standard previews during idle time', so Lightroom really only generates a preview when you start working on the image.
Photo of Andy Hasak

Andy Hasak

  • 13 Posts
  • 8 Reply Likes
I like having the standard previews be generated automatically. The operation has just been using a lot more resources after the update that made the previews generate during each batch of images that's imported, rather than sequentially after the import operation is done. Hope this makes sense. :)
Photo of Johan Elzenga

Johan Elzenga, Champion

  • 1541 Posts
  • 622 Reply Likes
You can still do that too. Import with embedded & sidecar, then after the import has finished, click on one of the embedded & sidecar badges in the upper left corner. Lightroom will ask you if you want to generate a normal preview for just this image, or for all of them.
(Edited)
Photo of Andy Hasak

Andy Hasak

  • 13 Posts
  • 8 Reply Likes
If I'm going to do it manually, I might as well generate minimal previews, and then generate standard previews from the menu after the import is finished. I've been doing it this way. Then the program doesn't have to do the work of making embedded and sidecar previews.
Photo of Johan Elzenga

Johan Elzenga, Champion

  • 1541 Posts
  • 622 Reply Likes
I don't think you understand this option. Lightroom doesn't make embedded previews and sidecars. Your camera does that. By using these camera-generated previews instead of having to build its own, Lightroom can import and display the images much faster. Just try it, the difference is really large.

Generating minimal previews is rather useless. Lightroom will still have to read the raw files to do this, so the speed gain is probably minimal compared to standard-sized previews.
(Edited)
Photo of Andy Hasak

Andy Hasak

  • 13 Posts
  • 8 Reply Likes
Thanks for your explanation, Johan.