Lightroom Previews are a very important part of how Lightroom works! There’s a bunch of different settings that Adobe provides to suit a plethora of computer configurations. So why the heck would you want to do something crazy like clearing a crucial part of Lightroom? I’ve got two reasons for you disk space and performance.

Reason 1 – Disk Space

Disk Space: a valuable and precious luxury if your wallet wasn’t stuffed at the time you decided to buy a laptop (like when I did). Preview files can really gobble up the GB if you aren’t paying attention.

It just happened to be a base model 2014 13″ MacBook Pro with Retina Display with only 120GB of solid state storage that I chose for my travel computer. As a student, I found myself with the dilemma of lots of speed without sufficient space (mainly I didn’t want to shell out a lot more money for a bigger internal drive, as I had plans in the future).

I wasn’t sure how often I was going to offload pictures onto it or carry pictures with me, but I did encounter a few instances in the past month. I shot a couple places here and there, but not too much.

I transferred settings and apps from my workstation computer and fired up Lightroom on my freshly purchased computer. I did the usual: culling, flagging, light editing. Then, a couple days later, I tried to throw another shoot on there and couldn’t due to low disk space! Turns out that the preview settings also transferred over from my workstation– it caused a whole lot of Smart Previews along with the normals previews to be generated!

Simply adjusting the preview settings won’t update or get rid of the older previews (plus I didn’t bring over all my pictures, so the previews were useless). So, thats when clearing them comes in!

This really is helpful if you’re no longer working with a bunch of pictures that have been sitting around for less than 30 days or so.

Reason 2 – Fixing things


Everyone knows that there are little gremlins working in every machine. A few glitches, in Lightroom, may perhaps be caused by the previews being corrupted. Symptoms may include missing previews, having error messages when importing pictures, creating smart previews, or even that it Lightroom can’t read a catalog (for whatever reason).

Solution: Delete these Files!

Let it be known that the Previews cache and the Smart Preview cache are different.

Typically, Lightroom stores the cache data for the Previews in a file next to your catalog in a filed named [Catalog name] Previews.lrdata and the data for the Smart Previews in [Catalog name] Smart Previews.lrdata.

Deleting the corresponding .lrdata file is all you have to do! The previews are used to speed up things when working on files. But you can always recreate them and may have a bloated database with previews from old shoots.

  1. Make sure that Lightroom is closed before you delete the file!
  2. When you delete the Previews.lrdata files, Lightroom will automatically recreate that .lrdata file the next time you start the program. Then it will regenerate previews as you go along.
  3. The Smart Preview cache file only comes back when you create a new smart preview. For more on Smart Previews and what they do, check out Howard Pinsky’s post on it: here.