Today’s Question: I have kept my photo collection on my C drive on my laptop, organized by year and month. I have duplicates of the collection on two external hard drives (J and G drives). Now I wish to delete all photos off my C (internal) drive, and work only from the J drive, with backup to the G drive. How do I manage this transition?
Tim’s Quick Answer: Assuming you have already made an exact copy of the photos on your internal hard drive to the external hard drive, with the exact same folder structure, I would recommend connecting the existing catalog to the external hard drive. This will involve fewer risks than trying to create a new catalog or deleting the photos from the internal drive from within Lightroom.
More Detail: It is important to keep in mind that your Lightroom catalog is simply managing information about your photos and referencing the source image files in their storage location. If you copy photos from one location to another outside of Lightroom, it is important to avoid creating a mismatch between the Lightroom catalog and your overall photo storage.
Normally the approach I would recommend in a situation like this would be to start by creating a reliable backup (or two, or more) of the photos on your internal hard drive. Then, within Lightroom, I would move all of the folders from the internal hard drive to the external hard drive you want to use moving forward.
In this case you have already copied photos from the internal hard drive to an external hard drive. As long as the copy is an exact match of the original (such as by using synchronization software), then you can connect the existing references to your photos to the new storage location.
The first step here is to “hide” the photos on the internal hard drive from Lightroom. This can be as simple as renaming the top-level folder for the overall storage structure, so that Lightroom will no longer find the folders and photos where they are expected. You can then right-click on any of the folders that now appear to be missing within Lightroom, and choose the option to reconnect the missing folder. In the dialog that appears you can then select the corresponding folder on the external hard drive. Lightroom should then recursively reconnect all folders on that external hard drive, so there are no longer any missing photos or folders within Lightroom.
In effect, what you’re doing here is redirecting Lightroom to the exact same folder and photo structure on a different drive. In the process you will not lose any information for your photos, since the catalog information is still available and you are simply referencing different copies of your photos.
Once that overall process is complete and you have confirmed that everything is in order in Lightroom, you can make yet another backup of your photos on the external hard drive, and then delete all photo folders on your internal hard drive to free up space. This last step, of course, should be postponed a little while to make sure all of your photos are safely being managed from your external hard drive before removing the photos altogether from your internal drive.