I always hear Lightroom catalog questions so I thought I’d tackle 5 things you need to know, or may not have known about catalogs in Lightroom.
1. The Lightroom catalog file is a physical file on your computer
If you ever want to find it, just go to your Catalog Settings (under the Lightroom menu on a Mac, or the Edit menu on a PC). Then look at the Location section. It’ll tell you right where your catalog is stored on your drive. There’s even a Show button that’ll show you right where the catalog is located.

1a. You can double-click a catalog to open it
Here’s a little bonus tip. Building off of the first tip above, your catalog is just a regular file on your computer. Just like when you double click a .PSD file it automatically opens in Photoshop, or word docs open in Word, .LRCAT files automatically open in Lightroom. So if you ever wanted to move a catalog from one computer to another, once you get it to the new computer just double click it to open.
2. Catalogs are cross-platform
Yup, the same catalog will work just fine on a Mac or PC. You could find your catalog (using #1 above) and move it between platforms and it’ll work the same on both.
3. You can store your catalog on an external drive if you use multiple computers.
If you work on a laptop and a desktop, you can always just store your catalog on an external drive and move that drive back and forth. Then use Tip 1a above, when you attach it to a new computer and just double-click the catalog to re-open it. Now, you’ll probably want a slightly fast drive for this. If you’re going to pull out your old USB 2.0 drive, then expect a sluggish experience.
4. If you use multiple catalogs, you can tell Lightroom which one to automatically open.
If you’re the multiple catalog type, and you have several catalogs, Lightroom will let you set up which one it opens automatically. Just go to your Preferences(under the Lightroom menu on a Mac, or the Edit menu on a PC). Then go under the General tab to the Default Catalog section. There’s a drop-down menu that let’s you choose exactly which catalog you want to open when you launch Lightroom.

5. There’s an Optimize Catalog feature in the File menu
This one sneaks by a lot of people. As time goes on, your catalog can become, for lack of a better word, less-optimized. That means things can slow down a little as you use Lightroom more. So it’s a good idea, that every couple of weeks you go to the File > Optimize Catalog menu and let Lightroom optimize itself to help keep things moving along.