• Welcome to the Lightroom Queen Forums! We're a friendly bunch, so please feel free to register and join in the conversation. If you're not familiar with forums, you'll find step by step instructions on how to post your first thread under Help at the bottom of the page. You're also welcome to download our free Lightroom Quick Start eBooks and explore our other FAQ resources.
  • Stop struggling with Lightroom! There's no need to spend hours hunting for the answers to your Lightroom Classic questions. All the information you need is in Adobe Lightroom Classic - The Missing FAQ!

    To help you get started, there's a series of easy tutorials to guide you through a simple workflow. As you grow in confidence, the book switches to a conversational FAQ format, so you can quickly find answers to advanced questions. And better still, the eBooks are updated for every release, so it's always up to date.
  • 18 October 2022 It's Lightroom update time again and there's a new AI-based Masking tools and a new Content-Aware Remove Healing tool, as well as smaller features, new cameras, lenses and bug fixes! See this blog post for Lightroom Classic and this blog post for the Lightroom Cloud Ecosystem changes.

Very large Collections / ~sets slow down Lightroom Classic?

Not open for further replies.


Active Member
Nov 28, 2010
The Netherlands
Lightroom Experience
Lightroom Version
Lightroom Version
Operating System
  1. macOS 11 Big Sur
My main Lr machine is still a 2013 MacBook Pro 15" Retina w/ 16GB RAM. My "private" catalog holds 150,000 images and tends to be quite slow, whereas a fresh catalog is still reasonably responsive. I always thought that my 150,000 images catalog was slow because there are so many images.

Then, while discussing config options on a Mac users forum, a contributor comes up with an interesting observation about collections. He says when his collection goes over say 15,000 images, and he has several of those in a collection set, at some point Lr will slow down. Then when he moves some of his collections to a different Collection Set, he's back up to speed. His guess is Adobe reserves a predefined block of memory for a collection set and then when that memory is full, trouble starts.

My question here is have you ever heard of this?

As soon as I get back home I will try to experiment with this myself. I have a bunch of smart collections, all in one collection set, containing my workflow, i.e. which images don't have flags, don't have ratings, no keywords and so on. For statistics I also have smart collections counting finished images, unfinished images etc. These smart collections may contain 50,000 or more images each, and they're all in the same collection set.


crossposted on Adobe forums
Not open for further replies.