Today’s Question: I successfully moved my photos and Lightroom from an old Macintosh to a new PC. However, none of my collections came over. How can I recover the collections?
Tim’s Quick Answer: Collections are a Lightroom-specific feature, meaning collection information is not stored with the photos themselves. Therefore, in order to preserve collections (and other Lightroom-specific features) when switching computers, you need to copy the Lightroom catalog file along with your images.
More Detail: When you want to move Lightroom from one computer to another, even if that involves switching operating systems, you can retain all of the information in your Lightroom catalog by copying the catalog files to the new computer, along with your photos.
The Lightroom catalog file (with a “lrcat” filename extension) can be used by the Lightroom application on both Macintosh and Windows computers. As a result, the process of migrating computers is relatively easy.
First, I recommend copying the entire contents of the folder that contains your Lightroom catalog from your existing computer to your new computer. You can determine where this folder is by clicking the “Show” button in the Information section of the General tab within the Catalog Settings dialog.
After copying the entire folder that contains your Lightroom catalog files to the new computer, you will want to make sure the photos themselves are available. This could be as simple as connecting the external hard drive that contains your photos to the new computer. Depending on the specifics of your workflow (and if you are switching platforms) you might also need to copy your photos to a new storage location as part of this process.
Once the catalog files and the photo files are available on the new computer, you can double-click on the catalog file (with the “lrcc” filename extension) on that new computer to launch Lightroom and open the catalog. At this point the photos will most likely appear to all be missing, because the specific path information to those photos will have changed. You can right-click on one of the missing folders and choose the option to “Find Missing Folder”. Then locate the applicable folder in the new storage location, and select it as the folder you want to reconnect. Lightroom will most likely then recursively reconnect all of the missing folders, but you may need to manually reconnect others as well.
With this approach you will retain all of the details for your photos, including Lightroom-specific features such as collections, pick and reject flags, history, and more.