deleted previews by accident

jonathanr2954463  wrote I deleted a large file of smart previews that was taking up too much space on my laptop. When I then went back to LR classic CC I saw that all of my regular LR previews were missing. It seems that I had accidentally deleted the file with all of my regular previews as well. How can I restore these previews short of re-importing all of the photos into LR from my external disc drives? Thank you.

Make sure those external drives are connected. Apparently they are not, right now. That is all you need to do. Lightroom will then rebuild the previews while you browse the photos, but it needs the originals to do that. You could also force rebuild them as advised above, but the key is that the originals need to be online.

The previews will rebuild as you browse the Library.

You can, if you like, rebuild all the previews using the following procedure.

• Click All photographs in the Catalog panel
• Edit > Select All
• Go to Library > Previews > Build standard-size previews

This could take a long time, so you might want to do it overnight.

Do not re-import. It's the wrong thing to do, and you risk losing all your edits.

Select thumbnails and from the menu choose:

Library >> Previews >> Build Standard Previews

You could select All Photographs in the Catalog tab or one folder at a time as needed.