Lightroom Previews Taking up 500GB

At any time, you can safely delete any file with a name that ends in …Previews.lrdata .

Those are preview caches, built to let you browse folders and collections more quickly, but because they’re just cached previews of your rendered edits, they are completely expendable. The only penalty is that the next time you browse a recently viewed folder or collection, those previews will need to be built again instead of instantly grabbed from the previews cache. But if you have a good recent Mac, preview building should be faster than in the past because that is now GPU-accelerated.

I used to throw them out when they reached around 30GB, but Lightroom Classic recently added a new option in Catalog Settings to limit the size of the previews cache, and I have set that limit. 

So how many catalogs do you regularly use? 

If there is only one you use regularly- what is the name of that catalog?

Your screen clip does not show the entire filenames with filetype-suffix included so it is difficult to comment.

-V13-4.LRCAT looks like it might be your current catalog (in 2026) but other previews from other catalogs are larger in size, and date of a preview file is not a good indication of use.

Preview caches  (eg. Catalog Name Previews.LRCAT ) are generally safe to delete as LrC will rebuild (slowly) previews for the open catalog.  (Do NOT delete your catalog file eg. Catalog Name.LRCAT)

But maybe ‘archive’ files to another location until certain you have not deleted anything related to your working catalog/s.