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:
