Merging and Moving Lightroom Catalogs

In Master Photography Roundtable by Jeff Harmon4 Comments

Listener Lightroom Catalog Question

This entire episode was the result of a question that was asked in our Facebook Group by listener Bryan Fishman:

” Can you point me to an episode on combining old Lightroom catalogs into one locally and storing photos externally. New MacBook Pro coming with just 512GB”

Bryan’s question is not a very lengthy one, but there is a lot of detail in there I want to make sure is covered for photographers who are newer to Lightroom.

What Is a Lightroom Catalog?

Think of a Lightroom Catalog like a physical notebook. Like in a school class you needed to write notes about the class in a notebook for later reference. Lightroom only knows things about photos after you have told it about where the photos are on your hard drive by writing that in the notebook. The import process is how you write into the notebook where your photos are at on your computer. Think of it like Lightroom titling a page in the notebook for every photo you import.

In addition to titling a page for every photo on import, Lightroom also looks inside each photo and pulls out data like the camera that was used, the settings of the camera (shutter, aperture, ISO), what lens was used, what focal length the lens was at, etc. All of this information goes on the page in the notebook for that photo.

Lightroom then notes down every step you make with each photo. When you rate your photos using the star, color, or flag ratings that information goes on the page in the notebook for that photo. When you move the exposure slider to the right, Lightroom notes down that change on the page for that photo. When you use an adjustment brush Lightroom writes down where exactly you painted over your photo on the page for that photo.

Where Is My Lightroom Catalog?

Your Lightroom Catalog can be stored on any hard drive connected to your computer. When you first start Lightroom it asks you if you want to create a new Catalog or if you want to load an existing one. Someone completely new to Lightroom is totally unprepared to make a decision here, so by default Lightroom will create a new Catalog located in your “Pictures” folder:

  • Windows: C:\Users\{your username}\Pictures\Lightroom\Lightroom Catalog.lrcat
  • Mac: /Users/{your username}/Pictures/Lightroom/Lightroom Catalog.lrcat

You can see exactly where your Lightroom Catalog is stored by running Lightroom and looking at your Catalog Settings (Edit > Catalog Settings on Windows and Lightroom > Catalog Settings on Mac)

On the General tab Lightroom has the location of the Catalog you have open and you can press the “Show” button to the right to have that location opened up in Finder on Mac or Explorer on Windows.

Is The Lightroom Catalog Cross-Platform?

Yes! It is a beautiful thing actually. You can create a Lightroom Catalog on a Mac and then copy it over to a PC and open it up in Windows without changing anything. Lightroom may have a hard time actually finding the photos linked in the Catalog depending on how it is you imported the photos on your computer, but that is a pretty simple problem to solve (right click > find missing folder).

I copy catalogs between Mac and Windows on a very regular basis. I use a MacBook Pro while on the road and then when I get back I merge the changes I made while out on the road to my main Lightroom Catalog on my Windows computer at home. It works flawlessly across platforms.

“Splitting” a Lightroom Catalog?

Going back to our analogy with your Lightroom Catalog being like a physical notebook, you can imagine you might have need for more than one notebook. In school, when you have more than one class, it might be helpful with your organization to have one notebook per class. Even if you don’t think you will entirely fill a notebook in one class, it might be helpful for you to not mix your notes from different classes in a single notebook.

You can think of it similarly in Lightroom. If it helps you from an organization perspective to have two different Lightroom Catalogs, like say one for Landscape and one for Portraits, then do that. Lightroom supports having multiple Catalogs extremely well. However, I highly recommend you only do this if there is a really good organization reason.

Lightroom is a powerful tool you can use to manage your photos. If you use more than one catalog you lose a little of that power because you can only manage the photos that are in that catalog rather than managing them all at once. If you feel like you need to separate your shoots some, try out the Collections feature in Lightroom as a powerful virtual way to organize things.

While on the topic of splitting Lightroom Catalogs, you may have heard at some point that you should split your Catalog after you have a lot of photos imported. Some have said after importing 10,000 photos, some at 20,000. All of them suggest doing this for performance reasons, to make Lightroom faster. I can tell you with 100% assurance after looking very carefully at Lightroom at a technical level, this is not true. Performance is not improved by splitting your catalog after importing a certain number of photos.

Yes, there are limits as to how many photos can go in a Catalog, but the capacity is so high you can use a single catalog for your entire life and not challenge it. Seriously, the underlying database technology Adobe uses for a Lightroom Catalog, called sqlite, is extremely capable and used by thousands of applications. Not just here with Lightroom.

I have done a lot of low-level technical testing of Lightroom and splitting your catalog simply because you have more than 20,000 photos imported does not improve performance. My catalog currently has a little over 100,000 photos and there is no detectable performance difference using it vs a fresh catalog with only a few hundred photos (something I do regularly to test things out).

Merging Lightroom Catalogs

We can finally answer part of Bryan’s question above. If you split your Lightroom Catalog for whatever reason (please don’t tell me it was to improve performance) and you decide you want to merge them back together it turns out there is a really great way to do that! Here are the three steps to take:

  1. Backup your Catalogs!!!!! Before you do ANYTHING with your Catalog files you should back them up. Lightroom can be setup to do this for you (see point #4 in Victoria’s blog post ) but you can also just use Finder on Mac or Explorer on Windows to copy and paste that .lrcat file to make a really simple backup.
  2. Make One the Master. Decide which of the two (or more) Catalogs is going to be the master Catalog going forward and open that Catalog in Lightroom.
  3. Import From Another Catalog. Lightroom allows you to import information about photos from another catalog:
    1. File > Import from another catalog
    2. Choose the other catalog that is not going to be the master going forward
    3. Lightroom will do a preparing step where it compares the two catalogs and finds the photos in the catalog being imported that are not in the catalog you have open
    4. You make some choices on which photos you want to import into the catalog you have open and what to do if there are photos that were in both catalogs then choose Import.
      NOTE: This process can take some time. You should plan on about 1 minute for every 500 photos. It is memory intensive, so to make it run the best it can you should close any applications you aren’t using.

Moving Your Lightroom Catalog To A New Computer

We have answered the first part of Bryan’s question, how to merge two catalogs locally. Now for the second part. When you get a new computer you have to figure out how to get your Lightroom Catalog moved over. Even experienced photographers may be unsure of how to do that because for most this is something they do rarely. Rather than write out those instructions here, I am going to refer you to my good friend Victoria Bampton who has a great step-by-step guide on your Lightroom Queen webiste:

One thing to remember in this is that the Lightroom Catalog is like that notebook where there is a page per photo in the notebook tracking things about your photo. That notebook, your Lightroom Catalog, DOES NOT HAVE YOUR PHOTOS!!!! Victoria does a great job explaining that in her guide as well, but just note that when you move your Lightroom Catalog you are not moving your photos.

For Bryan’s situation specifically, I recommend copying the master Catalog over to the new computer, then using Finder on Mac or Explorer on Windows to move the photos from the old computer to an external hard drive (he was worried there wouldn’t be room for the photos and the Catalog on the new computer). Then open up Lightroom on the new computer and it will not know where your photos are, so right click on a folder that has a question mark on it and choose Find Missing Folder to show Lightroom where the photos are now located on the external hard drive.



  1. Hi, long time listener, love the show. Just a quick thought about shuffling content. FYI the show hasn’t had anything about capturing pixels since July 4. I’m a big advocate of pre more than post (yes both are important but as a fairly new shooter I find creating and capturing content more helpful and interesting). Thanks

  2. I just want to say thank you on the very simplistic analogy of the catalog. I have been extremely frustrated as a brand new beginner in photography with no previous background in post processing. This was the best explanation of how to get started with Lightroom. I have been taking images for the last 2 months including a trip to Hawaii. Outside of downloading the images I have been lost. I have been listening to the podcast since January and purchased my camera in June.
    Yes more on taking pictures but this is also important so you know what to do with them when you get home. The problem is all the tutorials and reading I have done assume you know something about post processing. So I know I rambled but THANK YOU!

  3. Thanks Jeff so much for doing an episode on my question! I’m up and running on my new machine thanks to you and Victoria.

Leave a Comment