Why Does Lightroom Classic Take Up So Much Space? (Part 1)

by Andrew S. Gibson
Why Does Lightroom Classic Take Up So Much Space? (Part 1)

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Have you upgraded to Lightroom Classic yet? If the answer is yes, you may also have noticed a big reduction in the amount of available hard drive space on your computer. In fact, when I put the ideas in this article into action I freed up over 68GB of hard drive space! This figure may not mean much to you if you have a large capacity hard drive. But it can make a big difference if you don’t.

Many photographers use Solid State Drives (SSDs) as they are faster than regular hard drives. But they’re also more expensive and have less storage space. For example, my iMac’s SSD has a capacity of 256GB. I can work with that as I save most of my documents on external hard drives. The gain in speed, especially for working in Lightroom Classic, is worth it.

But it does mean that I have to keep an eye on how much space my Solid State Drive has, and so will you if you’re in the same situation. Everything on your computer, including Lightroom Classic, will run more slowly if you don’t have enough spare space on your main hard drive.

So, how much space do you need?

I’ve never been able to find an exact figure for this, but the rule of thumb seems to be 20%. Apparently if you have an SSD you can get away with less. In my case, with my 256GB hard drive, that means I need to keep 50GB free to keep my computer happy. In practice, I’ve had less than 30GB free and not noticed any difference in Lightroom Classic’s performance.

The 20% figure also applies to any external hard drives that you save photos and other documents on. Aim to stay within 80% of the hard drive’s capacity to keep Lightroom Classic happy.

You can have problems with storage space no matter which version of Lightroom you have, but the problem is bigger with Lightroom Classic because you can end up with three different versions of Lightroom installed on your computer.

Before you start

But before we go into the detail, there’s three things you should do first.

1. Back up your computer

It’s a good idea to backup the contents of your computer’s hard drive before you start messing around with Lightroom Classic installations. Especially important stuff like your Catalog and preview files. That way, you can easily restore any files you delete by mistake.

The easiest method is to use your computer’s dedicated backup software – Time Machine for Mac OS X and Windows Backup and Restore for Windows.

You can also copy all your Catalog and preview files to an external hard drive. This is important because you may have Catalogs and preview files left over from old Lightroom installations. It’s easy to delete the wrong files, so cover yourself by making copies.

2. Empty your Trash Can / Recycle Bin

This is kind of basic, but it’s easy to forget to empty your Trash Can (Mac) or Recycle Bin (PC) on a regular basis. You may be surprised by how much stuff you have in there, and how much space you free up when you empty it.

A word of warning – the Trash Can / Recycle Bin exists as a backup that lets you restore deleted files. Please make sure that there’s nothing in your Trash Can / Recycle Bin you might actually need before you empty it.

3. Check your documents

You may also be surprised by how many large files you have amongst your documents, especially if you have downloaded any video courses. Which of these can you save on an external hard drive? I checked mine the other day and found 17GB of files that I could move to another drive.

Now that’s done, let’s look at what you can do with Lightroom Classic itself to free up space on your hard drive.

1. Uninstall older versions of Lightroom

If you used Lightroom 6 and you’ve recently installed Lightroom Classic then you’ll find that you still have Lightroom 6 installed on your computer. On my Mac Lightroom 6 is a 1.6GB file, so that’s a lot of hard drive space to give to a program that you may no longer use. If you’ve installed Lightroom Classic and you’re happy with it then I see no reason to keep Lightroom 6 on you computer. Uninstall it to free up space.

To do so, go to the Creative Cloud app. Find your older version of Lightroom and click the arrow to the right of the blue button (1 – below). One of the options is Uninstall (2). Click it to start the uninstallation process.

How to save hard drive space with Lightroom

You can also do the same with even older versions of Lightroom. There’s no point in keeping Lightroom 3, 4, or 5 on your computer if you’re never going to use them. Lightroom 3, 4 and 5 aren’t handled by the Creative Cloud app, so it’s possible they are still installed on your computer and you’ve forgotten they are there.

You can apply this to other programs. If you have any unused programs on your computer, especially older versions of current software, you can remove them.

2. Remove old Lightroom Catalogs and preview files

When you upgrade to Lightroom Classic from Lightroom 6 Lightroom Classic updates the Catalog and creates a new Catalog and preview files that work with Lightroom Classic (but not older versions of Lightroom). As a result you end up with two lots of Lightroom files.

In the screenshot below, the green rectangle shows the Catalog and preview files used by Lightroom Classic (I renamed the Catalog so I didn’t get it confused with the older one). The red rectangle shows the files that are used by an older version of Lightroom on my machine (yours may have different names). These can be deleted. As mentioned earlier, it’s a good idea to back them up first just in case you need them or delete the wrong files.

Save Lightroom space

Most photographers use a single Catalog, but if you have more than one Catalog you need to be extra careful here as that makes it even easier to delete the wrong files by mistake.

3. Delete the Lightroom desktop app

If you don’t use the new Lightroom desktop app (read my article Which Lightroom Version Do I Need? if you’re unsure what it is) then there’s no point in having it on your computer.

Why uninstall the Lightroom desktop app? Two reasons. First, the program file itself is quite large (1.74GB on my iMac). Second, it creates a new Catalog file which is also quite large (called Lightroom Library.lrlibrary). You may not even know this file exists as it isn’t saved in the same folder as the Lightroom Classic Catalog.

This file can get quite big if you use the Lightroom desktop app as it stores your photo files in this file before it uploads them to Adobe’s servers. It deletes the photo files after they have been uploaded, which then reduces the Catalog size.

You can find the Lightroom Library.lrlibrary by opening the Lightroom desktop app, going to Preferences and clicking on Local Storage (1 – below). The filename and location are displayed in the window (2), but may be truncated due to the length. You can get around that by clicking the Browse button (3) to open the folder where it’s stored.

Saving space with Lightroom

Use the same technique to uninstall the Lightroom desktop app that you did for older versions of Lightroom. You can re-install it at any time via the Creative Cloud app if you change your mind.

How I freed up over 68GB of hard drive space

Save Lightroom space

So, where did my space saving of 68GB come from? Let’s take a close look at the numbers in the screenshot I showed you earlier. They really are quite amazing. The green rectangle shows the Catalog, Previews and Smart Previews files for my installation of Lightroom Classic.

The red rectangle shows the same files for my previous version of Lightroom. You can see that the Catalog is nearly double the size. The Previews folder is nearly 30GB bigger (I don’t know why, I can only guess that Lightroom Classic discarded some previews when I upgraded). The Smart Previews folder is also slightly bigger, but only because I’ve discarded some Smart Previews from Lightroom Classic.

Those three older Lightroom files add up to 50GB. The Lightroom app itself is another 1.6GB. Add in the 17GB of document files I moved to another hard drive the space saving comes to over 68GB. I’ve kept the Lightroom desktop so I can use it, but if I had deleted it I would have saved nearly another 3GB of hard drive space. Impressive!

More reasons why Lightroom Classic uses lots of hard drive space

The problems covered in this article are mostly specific to Lightroom Classic, but there are lots of other ways that Lightroom Classic expands to take up hard drive space. I’ll be covering those, and the solutions to the problems, in part 2. You can read that tutorial here.

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Jim Buckley January 12, 2018 - 10:40 pm

Thanks Andrew. Most useful. Because of some issues I’d been poking around inside Lightroom and saw I had two catalogues. I suspected that one was the old folder from the previous version of LR but wasn’t too scared to delete it! Now I have the confidence to do so. Thank you.

Andrew S. Gibson January 13, 2018 - 9:43 am

You’re welcome. Just make sure it’s backed up first in case it turns out to be important! It probably won’t but you never know…

Jae January 15, 2018 - 1:54 am

Thanks Andrew …

I have a small laptop [really small] that I had to purchase as an emergency because my PC up and died .. don’t have the cash to get something more powerful yet .. but do need to get work done.

Is it possible to delete the previews on LR CC [newest version] periodically? As the catalog itself goes back a ways .. but I don’t look at those older images as often .. “Once in a Blue Moon”

Just wondered if it was a good “housekeeping practice”


Andrew S. Gibson January 15, 2018 - 5:56 pm

Hi Jae, great question! If you go to Library > Previews you’ll see options for discarding 1:1 and Smart Previews. There isn’t an option to delete Standard Previews in Lightroom itself, but there is a way to do it. I’ll let you know what it is in the next article published on the website!

Jae January 15, 2018 - 11:49 pm

Awesome! Thanks Andrew! Just trying to keep work/life manageable … look forward to the next article!

Jae January 17, 2018 - 12:34 am

Gotta it! It’s great .. perfect .. thank YOU!

Nick Archer January 18, 2018 - 1:46 pm

Good article – very helpful, however, I have a question. I suspect that Lightroom is not very good at purging cataloges and previews when images are deleted – is this your experience and, if so, is there a way of forcing Lightroom to purge these storage areas of deleted images?

Andrew S. Gibson January 18, 2018 - 6:20 pm

Hi Nick, I don’t know if Lightroom has trouble purging previews that belong to deleted photos. You can use Jeffrey Friedl’s Bag-of-Goodies plug in to delete unwanted previews, but you have to do it before you delete the photos from your Catalog not afterwards. The details are in Part 2 of this article. Hope that helps!


Martin July 19, 2018 - 11:14 pm

Hi Andrew

Have you deleted backups from you LR backup folder? They also take up a lot of space and I now only keep the last 4, rather than 40!

Martin July 19, 2018 - 11:19 pm

Hi Andrew

Yes, you I see that you mentioned this in your second article.

Andrew S. Gibson July 22, 2018 - 9:40 pm

Hi Martin, yes, it’s important to delete unwanted backups as they use up LOTS of hard drive space. Which reminds me, I haven’t checked my backups for a while…probably got at least 30 to delete!

Bud Fridley January 21, 2020 - 12:18 am

I have so many backups…no clue which ones to delete…taking up so much space! please help!!!!

Andrew S. Gibson January 21, 2020 - 9:16 am

Hi Bud, are you talking about Catalog backups? As a rule of thumb you can keep your last three Catalog backups and discard the rest. That will free up lots of hard drive space for you.


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