What are other volumes in a container and how can I delete them?

When Apple released macOS High Sierra it introduced a new file system, APFS. It brought lots of under-the-hood changes to the way your Mac stores data, but, thankfully, we don’t need to get into those. One thing we should talk about, though, is "other volumes" in a container, because you might it mentioned on screen from time to time, especially if you use the Optimize Storage feature.

Other volumes: what does it mean?

In HFS+, the file system that was replaced by APFS, you could split a disk into different partitions. APFS gets rid of the concept of partitions and replaces them with containers. But containers differ from partitions. As well as having multiple containers on a physical disk, a container can have multiple volumes. For example, in macOS, your startup container has the main boot volume – usually called Macintosh HD – as well as the Recovery volume, Preboot volume,  and volume for virtual memory like swap files. 

Before we discuss what ‘other volumes in container are, let’s look at where message appears, in the Storage tab of About this Mac.

  1. Click on the Apple menu.
  2. Choose About this Mac.
  3. Select the Storage tab.

After a short time, when macOS has calculated it, you’ll see a colored bar describing how your storage is allocated. Most of the time the box looks like the image below. But sometimes you’ll see part of the box colored gray and the description ‘other volumes in container.’

Those ‘other volumes’ are the recover, preboot and virtual volumes. If you do see that message, it’s likely that the other volumes are taking up much more space than they should, because something has gone wrong. Unfortunately, reclaiming the storage space isn’t as simple as just getting rid of the other volumes, since they are crucial to the OS.

How to delete other volumes in container?

However, there are other ways you can fix the problem to free up space on your Mac, or get rid of the other volumes in a container message. Let’s look at the options. 

1. Get rid of purgeable space with CleanMyMac X

CleanMyMac X is one of my favorite tools for freeing up space, as well as doing general maintenance on my Mac. Don’t take my word for it though, well-known tech blog iMore.com called CleanMyMac X ‘the simplest way to keep your Mac clean’.

One of the new features in CleanMyMac X is the ‘Free up purgeable space’ tool in the Maintenance utility. This tool identifies space on your startup disk that contains files that macOS doesn’t need but which are only deleted when your Mac is running really low on storage. If you want to release that space before then, you can’t. Unless you use CleanMyMac X. Here’s how it works:

  1. Download and install CleanMyMac X (there’s a free version available).
  2. Launch CleanMyMac X.
  3. Choose Maintenance from the sidebar on the left.
  4. Check the box next to ‘Free up purgeable space’.
  5. Press ‘Run’.
  6. Wait. Identify space that can be safely purged takes a few minutes, but it won’t be too long.
  7. When it’s finished, you’ll hear an alert and see a message telling you it’s done. If there was a problem with other volumes in a container taking up too much space, it should now be fixed.

2. Create a new user account

Some Mac users have reported that creating a new user account allowed them to successfully reclaim storage from other volumes in a container.

  1. Click on the Apple menu and choose System Preferences.
  2. Select the Users & Groups pane.
  3. Click on the padlock and type in your admin username and password.
  4. Press the ‘+’ at the bottom left of the screen.
  5. Select Administrator from the dropdown menu and enter details for the new account.
  6. When you have created it, restart your Mac and log in with the new Administrator account.
  7. Choose About this Mac from the Apple menu again and then click on the Storage tab.
  8. The ‘other volumes in this container message’ should have gone.

3. Turn off content caching

Content caching allows you to store updates for other devices on your local network on your Mac, so that when they update, they don’t need to re-download  them from the internet, they just get them from the Mac. However, as well as taking up space, it can sometimes cause problems.

  1. Go to the Apple menu and choose System Preferences.
  2. Click on the Sharing pane.
  3. If  the box next to Content Caching is checked, uncheck it.
  4. Restart your Mac.

If none of the steps above worked, there is one more thing to try.

4. Check Activity Monitor

  1. Launch Activity Monitor from Applications>Utilities.
  2. Choose the Memory tab.
  3. Make sure the arrow next to ‘Memory’ at the top of the column is pointing downwards. If not, click it.
  4. Look for any processes that are taking up much larger amounts of memory than anything else.
  5. If you find one, select it and click on ‘Quit Process’.
  6. Check About this Mac again to see if ‘other volumes in container is gone’.

MacOS has made lots of improvement to the way it deals with storage space on your Mac, partly due to the lower capacity of the SSDs found in most Macs, compared with physical hard disks. However, sometimes these features go wrong, and it’s then that you may see the ‘other volumes in a container message.’ Happily, fixing the problem is not usually difficult, and it’s even easier if you use the ‘Free up purgeable space’ tool in CleanMyMac X.

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