"File not found" in Develop -- where are Smart Previews?

[eschurr]

When my PC is disconnected from my external hard drives, which is where is store all my original full sized files, i can't edit anything in Develop. It says "file not found."

This used to work fine, but now it doesn't.

I (think) I have LrC configured to use Smart Previews, which i thought meant i could use Develop even in my original full size files are stored externally.

I mostly shoot on my Galaxy S25 Ultra and sync to LrC via the cloud.

I'm using LrC 14.2 on a Windows Surface Book 2.  Everything is updated to the latest versions.

[dj_paige]

I'm guessing you don't have smart previews for this photo. Can you show us the entire Library Module screen with this photo selected, so we can see the Grid with the photo selected, and the Histogram and right side panel? Use the "Insert Photos" icon to include your screen capture in your reply; do NOT attach files.

[JohanElzenga · Accepted solution]

The preference setting you encircled in your screenshot only tells Lightroom Classic to use smart previews instead of originals, if a smart preview is available. It does not tell Lightroom Classic that it must generate smart previews, however. You must tell Lightroom Classic to do that when you import images. Or later, by selecting the images and then using the menu 'Library - Previews - Build Smart Previews'. Apparently you did not do either, so you don't have a smart previews for that image.

[Conrad_C · Accepted solution]

All Smart Previews for a particular catalog are in a file in that catalog’s folder; the file is named

"…Smart Previews.lrdata"

As the others are saying, the question is which images have Smart Previews in that file, and they usually don’t get them automatically. I think the only way they would have them automatically is if Build Smart Previews is enabled in the Import dialog box, but that option doesn’t apply to images imported by syncing down from a mobile device through the Lightroom cloud as you are doing. 

If you want to know specifically which images do have Smart Previews, you can tell by looking at an image in the Develop module, or you can generate a list using a Smart Collection. 

In the Develop module, the Smart Preview indicator is under the histogram as shown in the picture below. If it only says Original Photo, there is no Smart Preview, but you can generate one by clicking that indicator. The picture shows before (left) and after (right) generating a Smart Preview.

If you want a list of which images in the catalog have Smart Previews, you can set up a Smart Collection as shown in the picture below.

If you want to generate Smart Previews in bulk, select them and use the command that JohanElzenga already mentioned. 

[eschurr]

Thank you so much for your quick and very helpful replies.

You are all correct that i didn't generate Smart Previews for these images. I thought LrC did that automatically for me! When i used to import from my SD card I had my import configured to generate Smart Previews. I thought LrC did that automatically for files imported via LrM but I'm wrong!  

Sure seems like that would be a good feature to add:  generate Smart Previews automatically when syncing from LrM.