What Time Machine Doesn’t Back Up

Apple:

You can use Time Machine, the built-in backup feature of your Mac, to automatically back up all of your files, including apps, music, photos, email, documents, and system files.

Maxwell Swadling:

Time Machine backups skip a bunch of files. Some you might expect, some might surprise you!

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The Voice Memos iPad App On The Mac seems to exclude the one bit of data it is responsible for saving... recordings...

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I covered in another blog post that the key Photos Photo Library database file is missing[…] Missing this and all its associated files needed to restore Photo Libraries without data loss.

I don’t use Photos enough to know what its database stores that isn’t in iCloud Photo Library. But print projects definitely don’t sync using iCloud, and they can represent a huge time investment. It looks like some project-related files do get backed up—maybe Photos is able to rebuild them into a new database?

But I would feel more comfortable with everything backed up and not relying on a potentially lengthy or buggy rebuild. Some other backup software will exclude files by default, but you can adjust the settings to manually include them. That’s not possible with Time Machine.

Maxwell Swadling:

I was genuinely surprised iCloud Drive wasn’t backed up because I think of time machine as having the “go back in time a year and see what the file was” feature, which doesn’t work on iCloud Drive files!

This sounded really bad to me, because iCloud Drive files don’t necessarily get stored in the cloud, either. Your Mac may not currently have a network connection, and sometimes uploads get delayed or wedged. Once in the cloud, the files are subject to beta bugs, and you have only a very limited ability to restore the latest version of individual files that it thinks you deleted.

But Howard Oakley says iCloud Drive does get backed up, and I do, in fact, see the files in my Time Machine backups.

Maxwell notes that Time Machine doesn’t back up folders which are found in iCloud Drive, but in my experience it’s not as simple as that. The rule seems to be that Time Machine does back up the contents of your current iCloud Drive, but only those items which are currently stored locally. Any items which have been evicted to iCloud, and are only represented by local stub files, aren’t backed up.

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For Time Machine to be able to back up a file evicted to iCloud Drive, that file would need to be downloaded to local storage first. Imagine having a 512 GB internal SSD, and over a terabyte of documents in your iCloud Drive, almost all of which were evicted from local storage.

This makes sense and is probably the only reasonable thing for Time Machine to do. But, to me, it’s yet another reason to avoid the Optimize Mac Storage option. If your files in iCloud Drive are important enough to sync between devices, they’re probably important enough that you want to have your own backups of them.

Previously:

• iCloud Drive Features Removed/Postponed
• Trusting iCloud Drive
• iCloud Data Loss With macOS 10.15 and iOS 13 Betas
• Document Versions and iCloud
• iCloud Drive Breaks the macOS Command Line
• Solving Problems With iCloud Drive
• How iCloud Drive Can Break Time Machine Backups
• Successful iCloud Desktop and Documents Folder Storage
• How iCloud Drive Deletes Your Files Without Warning
• What Backblaze Doesn’t Back Up

Update (2019-09-27): Jesse Squires:

Now that we sort of understand the layout of ~/Library/Mobile Documents/, where the hell are our iCloud Drive documents stored? Those live in com~apple~CloudDocs/. If you cd there, you should see all of the “custom”, non-app-specific files that you’ve stored in iCloud Drive. These should match what is viewable in Finder.

This is the directory that we want to backup. We can use rsync to do that. (Side note: the way that rsync handles paths is a bit odd. It doesn’t like relative paths, or ~, or escaping spaces in directory names. Thus, this script uses absolute paths with spaces.) You just need to fill-in the USER and DEST variables.

Update (2021-09-08): See also: Howard Oakley.

Backup iCloud Drive iCloud Photo Library Mac macOS 10.14 Mojave Photos.app rsync Time Machine Voice Memos

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