When will you build thumbnails automatically?!

[Katrinochka]

So many years of development, and LR still only renders grid view thumbnails for the visible screen area! Isnt it obvious that we need thumbnails FOR ALL images without the workaround of building previews. 
same goes for LR mobile. 
What are your guys getting paid for at the usability department, I cant guess! Oh, well, they havent yet solved the lags in grid view scrolling on hi res mac displays, so how dare I ask for self-generating thumbnails

[JohanElzenga]

This is a user-to-user forum. We are not Adobe. For feature requests, go to https://feedback.photoshop.com. Search for your feature request first. If it is already requested by someone else, then don't create a new thread but add your vote to the existing request.

[Katrinochka]

Adobe reads it!

[JohanElzenga]

No, their engineers don't read this forum. That is why you should use the proper one.

[Rob_Cullen]

When I import my photos to Lr-Classic, I sit back with a coffee and allow Lr to build Standard or 1:1 previews as they import.

I never see Previews needing to 'build' as I scroll in Grid view.

(When I say "never"- I have seen this once after deleting the previews cache file, but only then)

[JohanElzenga]

The OP is correct, this is an issue that has plagued Lightroom since version 1. Lightroom does render previews for "off grid" images on import like you say, but not later on (if they need to be rendered again). For example: If you select 100 images (meaning many will be "off grid") and apply a preset to them, you will see that the "off grid" previews will only be updated when they come into view after scrolling. Even if that is hours or even days or weeks later.

That also explains why deleting the entire previews cache does not recreate a previews cache of the same size in a matter of hours or a few days. It will take a long time, because previews of images you did not look at in the grid so far will not be rendered until you do look at them one day. And for old images that may take months. In fact, this may be exactly the reason why Adobe chose to do it this way: to allow you to keep the preview cache smaller than a cache of previews of every single image in the catalog would be.

[Katrinochka]

If you have a hundred thousand images in you library, you may not want to create previews for all of them at once. There are many use case scenarios where you end up with a grid view of empty thumbnails and it is very stupid to not build the thumbs automatically. 

P.S. What do you do with the same issue in LR mobile?

[JohanElzenga]

In Lightroom Classic you can force a build of previews. Select the images, then choose 'Library - Previews - Build Standard-sized Previews'.

Lightroom Mobile should not show empty thumbnails when it's fully synced, but storing smart previews locally helps if you use it without an internet connection.