Why Is Lightroom Always Generating Thumbnails?
I really like working in Lightroom Classic except that—despite continually updating to newer versions that promise performance improvements and newer Macs with faster processors, SSDs, and more RAM—it still feels slow. Maybe it’s my imagination, but I don’t think it was always thus. I think I used to be able to import a thousand photos and do stuff in the app during that process. Now, the app almost locks up during the initial phase of the import, and it bogs down the entire Mac. Sometimes I can’t even monitor the CPU use with App Tamer because the XPC messages between its daemon and menu bar item get delayed.
Imports are not the main problem, though, because I can generally start them before I take a break and let the Mac chug away while I’m gone. What really gets in the way is that—unlike Apple Photos—it can’t smoothly scroll through a grid of thumbnails. Some of them are inevitably blank or blurry, and Lightroom shows three dots in the upper-right corner to show that it’s busy working. Sometimes a given thumbnail will load in a few seconds, but other times it takes more like minutes. It does not seem to do any pre-loading so that when I press Page Down the next screenful of thumbnails will already be ready. It seems to wait until they are in view before beginning the work.
I’d like to be able to tell Lightroom to pre-generate all the thumbnails, and keep them stored, so that scrolling is always fast. But my understanding is that there’s no such command. Thumbnails seem to be tied to the generation of previews. I have Lightroom set to auto-generate previews on import, but that doesn’t do the job. Choosing Library ‣ Previews ‣ Build Standard-Size Previews doesn’t seem to help. Choosing Library ‣ Previews ‣ Build 1:1 Previews does help somewhat, though I’m not sure why building huge previews vs. standard ones would help more with thumbnails. But, even then, if I scroll through a few thousand photos whose 1:1 previews I just rebuilt, I still see the … indicator on some thumbnails. Many that don’t show that indicator are blurry for a few seconds. Browsing within a single collection, I can slowly scroll down to the bottom so that all the thumbnails are eventually loaded, but they don’t all stay loaded. Doing the same scroll again seems to cause some of them to be regenerated or at least reloaded.
Previously:
9 Comments RSS · Twitter · Mastodon
Did you by any chance change the "Standard Preview Size" in the Catalog Settings or do you have a very old catalog from before using a 4K or 5K Display?
If the Preview Size is anything other than the recommended value (prefixed by "Auto"), than Lightroom *will* generate a new preview on viewing the image (except when the original is not available). That way your computer slows to a crawl after viewing only about 30-50 images or fast switching between them.
I recently had this problem, switched the preview size to 2880px for a 4K display (as macOS uses a 5K desktop behind the scenes), generated new previews and it's a bliss since then.
Only downside: the catalog will grow considerably larger.
I also changed the maximum size in "Camera Raw Cache Settings" (Tab "Performance" in Lightrooms Preferences) from 5 to 25 GB – although that may only be homeopathic, as I read it online and didn't check it's effectiveness.
@Christian That’s good advice. It’s a very old catalog, but the preview size has always been set to Auto. I think the previews are working because it’s quick to view individual images. It’s just the thumbnails that seem be off.
I’m not sure what’s going on with the Camera Raw Cache. I had it set to 5 GB and it was using 8 GB, but the files were mostly not modified recently despite heavy use the last few days. I thought it was for RAW images, which I haven’t really shot in years, but maybe it also applies to HEIC. I don’t think this cache should affect thumbnails, just preview generation and Develop performance, but I’ll bump it up just to see whether it helps.
My experience has been the same. It's why I still miss Aperture a decade after it was discontinued. I've been using Lr Classic for a good part of that decade and moving through images has always felt like stirring molasses. Some years it's cold, stiff molasses and I find myself actively avoiding viewing/editing my images. Some years it's warmer. Aperture had its problems (so many crashes and lack of support), but at least looking at my images wasn't one of them.
Lightroom has rather recently switched away from using .lrpev pyramid files to store previews of various sizes in a single proprietary file. It now uses individual JPEG files. It seems the conversion happens lazily as you browse your library. With a little luck the situation will improve once Lightroom has finished converting all preview files.
Note: I don't actually use Lightroom. I loved Aperture. It worked just the way I expected and had all the editing features I need. Having tried many alternatives, I admitted defeat and stuck with Apple Photos and basically stopped editing photos. When the need arises, I export the original, edit in DxO and import a second copy.
@Pierre Thanks for that info. I don’t think the conversion is the issue here since the slow folders I’ve been working with lately are all new photos, and as I said it’s still not great even after manually rebuilding 1:1 previews.
Thank you so much for this - I thought I was weird, or doing something wrong. Lightroom staggers along for me, even on vastly superior hardware to my old Aperture setup, and it's never not been painful to use for photoshoot triage and organisation. It baffles me that this level of performance somehow seems to be accepted.
I began using Lightroom with version 1 and transitioned to Mylio (www.mylio.com) around version 6 due to performance issues. If you aren't doing any advdanced RAW adjustments, Mylio's editing capabilities might suffice.
Mylio excels as a catalog/photo organizer, remaining very snappy even with a collection of 150,000 photos. Its synchronization capabilities are particularly impressive, allowing catalogs and thumbnails (as well as previews and originals, if desired) to be synced across multiple devices, including mobile phones.
It’s certainly worth considering Mylio as a potential replacement for Lightroom.
