Your photos are some of your most valuable data on your Mac, containing special memories that you want to make sure to preserve. Making regular backups is a critical step in managing your Photos libraries, and there are several methods you can use to make those backups, depending on your particular setup.
Time Machine is a feature that comes built-in to macOS and is a very good and simple way to keep your photos backed up. Once you have an external drive set up with Time Machine, all your Photos libraries will automatically be backed up for you in the background. Time Machine can be used with a USB/Thunderbolt external drive attached to your Mac, as long as the drive is formatted as MacOS Extended or APFS, or with some NAS systems that are compatible with Time Machine (consult your NAS’ documentation for details on setting that up).
If you only occasionally have a backup drive connected to your Mac, or don’t want everything on your machine backed up like Time Machine does, you can back up your libraries manually by simply copying each one to an external drive. Each library is a self contained unit (with the notable exception of referenced photos), so you can just copy the library package to your external drive either using the Finder or the File > Duplicate Library command in PowerPhotos.
Cloud storage services
Some cloud storage services (e.g. Dropbox, Google Drive) can be used to store a backup copy of your library, but only as a one way backup and not to sync between multiple Macs. (read more here about why you can’t sync libraries with cloud services). If you store your library (or periodically make a copy of your library) in the folder that syncs with your cloud service, then that will upload a copy of those files to the cloud so that they can be restored if your Mac should be lost, stolen, or otherwise meet an untimely demise.
Note however that iCloud Drive will ignore any photo library that you place in the iCloud Drive folder and will not upload it at all. The only way to put your photo library in iCloud is to use iCloud Photos.
Cloud backup services
These are cloud services that are designed to do a one way back up of your data to the cloud, services such as Backblaze, CrashPlan, and a number of others. These differ from cloud storage services like Dropbox or Google Drive which are aimed at syncing files between multiple computers.
Most cloud backup services will do a good job of backing up your photo libraries to their cloud storage. If you store any of your libraries on an external or network drive, the one thing you’ll want to check is if your service supports backing up content that you store on external drives, or if it will only back up what’s on your internal drive.
iCloud Photos and backing up
iCloud Photos is a very useful service that lets you easily have a copy of your photos in the cloud and access your photos from multiple devices. However, you should not rely on iCloud Photos to be your primary backup solution for your photos. The main reason for this is because any changes you make to your photo library automatically get synced to iCloud, and to the rest of your devices. This includes things like deleting photos and albums, which means if you accidentally delete something you want to get back, you won’t be able to get it from iCloud Photos. You need to have another backup strategy in addition to iCloud Photos.
Backing up and the “Optimize Storage” iCloud Photos option
If you use iCloud Photos with the “Optimize Storage” option enabled, then Photos will only download the full size versions of your photos on demand, e.g. when you go to view or edit individual photos in full size. This means that if you directly back up your Photos library, you will only be backing up whichever photos that Photos has happened to download to your local hard drive.
If you don’t have room on your internal drive to store everything that’s stored in iCloud Photos, then you’ll need to set up a separate library on an external drive that syncs to iCloud using the “Download Originals” option, then also back up that library to ensure you have backups of all your photos. Here are two way you can do that.
If you have a setup where you can keep your external drive connected to your Mac most of the time, then you can do the following:
- Create a new user account on your Mac and sign into your same Apple ID on that account.
- Enable fast user switching
- Login to that account and open PowerPhotos.
- Use PowerPhotos to create a new photo library on your external drive, then open that library in Photos.
- Open the Photos preferences/settings window and click the “Use as system photo library” button. Then go to the iCloud section, enable iCloud Photos, and select the “Download Originals” option. Photos will start to download everything from iCloud into the library on the external drive.
- Don’t log out of the account, but rather use fast user switching to switch back to your regular user account.
- You can pretty much just leave the setup like that, and as long as the second account remains logged in in the background, it will continue to download data from iCloud. If you restart your Mac at any point though, you’ll need to remember to log back into that second account so it can keep syncing with iCloud Photos.
If you can only plug in your external drive periodically, you can still use the procedure above, or you do something similar as follows:
- Instead of creating a new user account, just create a new library on the external drive, then open the library in Photos.
- The same as above, switch that library to be the system library, then enable iCloud Photos with the “Download Originals” option. This will temporarily disable iCloud syncing with your default library.
- Allow Photos to download all the content from iCloud Photos. You can check on progress by going to the “All Photos” view in Photos and scrolling all the way to the bottom of the photo browser.
- Once it’s done downloading everything, reverse the procedure. Use PowerPhotos to open your original library up in Photos, make it the system library, and reenable iCloud Photos there, but with the “Optimize Storage” option selected.
- For further backups, repeat steps 2-4 above whenever you have a chance to plug in your external drive for a little while.