When first introducing macOS 10.12 Sierra, Apple made much of Optimized Storage, a marketing term that encompasses various settings and cloud-related technologies for moving data from a Mac’s space-constrained local drive to the cloud. In “Explaining Sierra’s Optimized Storage” (19 September 2016), I tried to lay out what Optimized Storage covers, explain the Storage Management window interface, and give suggestions about what you should or should not enable manually. Since Optimized Storage deletes data from your local drive such that it may not exist in your backups, you should be aware of the implications of turning it on.
Unfortunately, because Sierra prompts you to enable Desktop and Documents folder syncing during installation and may enable the associated Optimize Mac Storage checkbox by default as well, many Mac users are unwittingly enrolling important data in Optimized Storage. Worse, reports have started circulating that Sierra may have enabled some previously disabled Optimized Storage features during the 10.12.1 update. That’s not OK.
For the record, I don’t believe that Optimized Storage is inherently evil. Some of its options, such as deleting the local copies of watched movies and TV shows purchased from the iTunes Store, have few downsides. However, many people wish to maintain complete control over local storage, so I’ll explain how to disable all of Optimized Storage’s options in this article.
iCloud Drive & Desktop and Documents Folder Syncing -- Technically speaking, Desktop and Documents folder syncing isn’t part of Optimized Storage. Its goal is to store your documents in iCloud Drive so you can access them from any of your Apple devices.
However, Optimized Storage can apply to all iCloud Drive-based documents and data, including the Desktop and Documents folders if they’re being synced through iCloud. If Optimized Storage does decide to start deleting local files to free up space, those files are most likely to come from your Documents folder. To keep your Desktop and Documents folders out of iCloud, and to ensure that data that is in iCloud is always mirrored locally, open System Preferences > iCloud > iCloud Drive > Options, and deselect both Desktop & Documents Folders at the top of the list and the Optimize Mac Storage checkbox at the bottom.
Be aware that turning off Desktop and Documents folder syncing is stressful. When you do so, in System Preferences > iCloud > iCloud Drive > Options, Sierra tells you that all your files will be available only in iCloud, which seems wrong: if you’re turning off syncing, you’re doing so because you want them locally. However, that dialog is followed immediately by another that tells you that you can recover your files from iCloud Drive.
In fact, what happens when you turn off that feature is that Sierra recreates empty Desktop and Documents folders in your home folder. You can’t replace those folders, so it’s not possible to drag the old Desktop and Documents folders from iCloud Drive to your home folder. Instead, you must open each folder in iCloud Drive and move (Command-drag) its contents to the new local Desktop and Documents folders in your home folder. You can try to delete the now-empty Desktop and Documents folders from iCloud Drive, but in my experience, iCloud keeps recreating at least the Desktop folder.
Photos -- Given the ease of taking and storing photos and videos, your Photos library may occupy more space than anything else — I’m not a prolific photographer and mine is still over 110 GB. If you have multiple Apple devices, using iCloud Photo Library lets you access, edit, and manage your photos from any device, which is great, even if it almost always requires that you pay for additional iCloud Drive space.
iCloud Photo Library was one of the first places where Apple dipped its toes into optimizing storage because many Photos libraries are far too large to fit on iOS devices. Plus, it’s not uncommon for someone to have an iMac at home but want to play with photos on a space-constrained MacBook Air while on vacation.
My recommendation is to keep Optimized Storage enabled for all iOS devices and secondary Mac notebooks where space is at a premium, but to turn it off on your main Mac so your photos are always included in your backups. To do this, open Photos > Preferences > iCloud, and select “Download Originals to this Mac.”
Mail -- If you work with people who send around presentations or videos on a regular basis, Mail is likely consuming a significant amount of drive space. Email messages themselves are small, so there’s no win in deleting them, but attachments are another story.
In previous versions of Mail, you could either download all attachments or leave them all on your IMAP server. Sierra’s version of Mail adds a third option to download only recent email attachments. When you open a message whose attachment hasn’t been downloaded, you can click a button to get it. If you want to see how much space you’d save by downloading only recent attachments, launch System Information, choose Window > Storage Management, and click Mail in the sidebar.
Apple has bundled these features into Optimized Storage, so if you want to make sure that your local mail archive always contains both messages and attachments, so in Mail, go to Mail > Preferences > Accounts > accountName > Account Information and choose All from the Download Attachments pop-up menu. Make sure to do this for each of your accounts!
iTunes -- Video can consume massive amounts of drive space, but it’s also slow to download. If you regularly purchase movies and TV shows from the iTunes Store, you can use Optimized Storage to remove watched videos from iTunes automatically. But what if you’re buying content for a child who wants to watch things multiple times, or you want to ensure you can watch anything again without having to download again over a slow Internet connection?
To turn off Optimized Storage in iTunes and ensure that all the videos you purchase from the iTunes Store stick around even after you’ve watched them, navigate to iTunes > Preferences > Advanced and deselect the “Automatically delete watched movies and TV shows” checkbox.
Empty Trash Automatically -- All the previously mentioned features of Optimized Storage involve deleting the local copy of a file under the assumption that it can be retrieved from the cloud if necessary. The final aspect of Optimized Storage that you might want to turn off is different — it’s an option in the Finder that automatically deletes files in the Trash after they have been there for 30 days.
Frankly, there should be no downside to enabling this option. You should never depend on being able to go into the Trash to bring back a file that you deleted more than a month before. Just don’t delete any file that you might want again.
That said, if you want more control over when your Trash is emptied, go to Finder > Preferences > Advanced and deselect “Remove items from the Trash after 30 days.”
Manage Storage Manually -- If you’re uncomfortable with Optimized Storage but are still running out of space on your Mac’s drive, you can use the new Storage Management window to identify and delete large files. Open the System Information app, choose Window > Storage Management, and look at all the sidebar categories underneath Recommendations.
With a little attention paid to the old versions of apps, unnecessary downloads, and unexpectedly large documents scattered around your drive, you can often clear a surprising amount of space in just a few minutes while retaining complete control over your local storage.