Skip to main content
aledeniz
aledeniz
Participant
December 13, 2018
Answered

Rebuilding previews from embedded/sidecar to minimal?

  • December 13, 2018
  • 1 reply
  • 2783 views

I am a complete newbie with Lightroom Classic CC.

I am reading the reference, viewing the tutorials, and following Matthew Pizzi's Lightroom CC Fundamentals course on PluralSight.

To better understand the Catalog requirements, I have imported ~108,000 photographs in a single catalog, selecting embedded/sidecar as preview type.

My workstation (Windows 10 on Intel i7, media drives on dedicated SAN in RAID 10, all enterprise class hardware) took a couple of days to complete that.

The resulting Lightroom Catalog Previews.lrdata folder is 323 GB. For a number of reasons, I think this is higher than I'd like [1].

I do wonder if there is a way to rebuild the previews as minimal, or if I have to start a new catalog and import from scratch.

Or should I instead try to rebuild the previews as standard, selecting medium or low quality?

Also, what happens when there are not embedded/sidecar previews? Does the import fall back to standard?

[1] of those ~108k, ~44k are my personal ones (half RAW+JPEG, half JPEG, I think I may have not imported the JPEG version of the RAW ones), while ~64k (all JPEG) are representative of a job (a smallish one, so I added my own pictures to make the exercise more representative).

Corrected a typo. Message was edited by: Alessandro Riolo

This topic has been closed for replies.
Correct answer cmgap

You won't have to start a new catalog to rebuild the previews file with minimal if that is really what you want to do. Keep in mind that minimal previews are the lowest quality preview and you won't be able to zoom in. You can however choose to rebuild, select minimal to reduce the file size and create Smart Previews selectively.

If you want to rebuild your preview files:

- Quit Lightroom, locate the previews file (Previews.lrdata) in your Lightroom folder and rename the file. You'll delete it later once you've confirmed the new preview file is as expected.

- Restart Lightroom > Select all images in catalog and go to Library menu > Previews > Build Minimal-Sized Previews

Delete the old previews file after checking to make sure that all is working as expected.

1 reply

cmgap
Community Expert
cmgapCommunity ExpertCorrect answer
Community Expert
December 13, 2018

You won't have to start a new catalog to rebuild the previews file with minimal if that is really what you want to do. Keep in mind that minimal previews are the lowest quality preview and you won't be able to zoom in. You can however choose to rebuild, select minimal to reduce the file size and create Smart Previews selectively.

If you want to rebuild your preview files:

- Quit Lightroom, locate the previews file (Previews.lrdata) in your Lightroom folder and rename the file. You'll delete it later once you've confirmed the new preview file is as expected.

- Restart Lightroom > Select all images in catalog and go to Library menu > Previews > Build Minimal-Sized Previews

Delete the old previews file after checking to make sure that all is working as expected.

A
ATEriksen
Known Participant
November 14, 2023

Hello @cmgap  I've done facial recognition work on about 500k images. If I delete previews file I could potentially lose that work/data too said Adobe Support. They have no internal documentation on this.

 

I'm also not sure if moving or deleting the preview file will also "detatch" the facial recognition data (keyword vs image location) from the preview images so that I need to do all work all over again. If pixel size change when location of face would too. Adobe couldn't confirm either if this happened. There is nothing in their own internal documentation about this.

 

Either "regenerate standard previews" from menu should work on previously generated images/previews when settings change, or, ask user if he/she like to regenerate using the new settings.

Any "hacking and whacking" files around in important workflows that may end up losing or redoing work is a failed strategy. The function "regenerate previews" simply doesn't work properly. Either a bug or severely underprioritized function since this option existed since day 1. 

 

Regards,

Aleksander

dj_paige
dj_paige
Legend
November 14, 2023

@ATEriksen 

best to start a new thread and describe your problem there, rather than attach your problem to some old thread about some other problem.

 

Terms & ConditionsAccessibility statement
Using the community Terms of use Privacy Cookie preferences Do not sell or share my personal information ad choicesAdChoices