You can’t manually force clearing this cache of images from within Lightroom.

Set up your Lightroom cache so it doesn’t take over your drive

And then these cached images stay there, taking up your hard drive storage without so much as saying hello.

When you import photos to Lightroom, the software copies them to another folder on your computer’s local drive before uploading them to the cloud. However, this is not the hard drive-eating behavior that I’m talking about here: Rather, it’s a back-end caching feature of Lightroom that makes it quicker to work on your files. You can also tell Lightroom to store certain albums locally. Now, your Lightroom catalog can be synced with a Lightroom Classic catalog, which (as I will explain in a future article) results in all your cloud photos being downloaded (again) to your computer, even if you have local copies stored there already. This contrasts with Lightroom Classic, which links to files on your computer’s local storage. Lightroom works by uploading the photos that you import to your Adobe cloud storage, and these originals in the cloud are then used as the basis for all edits. Eventually I stumbled onto Lightroom being the culprit. I kept wondering why my computer hard drive was always full. Did you know that Lightroom might be eating up your computer’s hard drive space, without your knowledge? I didn’t.

Mac hard drive space low