Free Space Required for Modern macOS Upgrades
Sierra (Mac OS X 10.12) had a minimum drive capacity of 8.8 GB but really needed more like 12 GB; however there wasn’t a hard number sanity check that I personally ran into. This was 2016 and the amount of free space required to do an upgrade would increase dramatically.
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The net result is that when doing the last few upgrades, they have required 12+GB for the installer itself (which can be run from a USB drive) and up to 44GB for the installer to do the work it needs to do, so a total of up to about 56GB. Therefore, scoping policies to run an updater without causing undo issues to end users it’s entirely appropriate to make sure they have the amounts of free space indicated per version. Given that drives can be a terabyte in size, this doesn’t seem wildly inappropriate; however, many organizations still buy devices with 256GB drives (thus going from an eighth in the 64GB drive era to a quarter of common drive space required to be free for certain upgrades on smaller drives today).
These days I find that I want about 150 GB for a test partition that will include macOS, Xcode, and enough space to clone my Git repo and run the tests.
Previously:
- OmniDiskSweeper 1.14
- diskspace Tool to Report APFS Free Space
- Big Sur Really Needs Real Free Space
- Check Free Space Before Updating to Big Sur
- iOS 9 Space Savings
Update (2022-11-09): Nick Heer:
Users are disrespected by increasing and surprising bloat in applications. For work, I need to run the Microsoft OneDrive client on one of my Macs, and I was surprised to see that it recently crossed the 1 GB threshold. This is a file syncing utility.
Update (2022-12-02): Adam Engst:
I was reminded of it when TidBITS reader Marc Heusser wrote to tell us that upgrading from macOS 12.6.1 Monterey to macOS 13.0.1 Ventura on an M1 MacBook Pro with insufficient free space resulted in errors that prevented the MacBook Pro from booting.
Update (2022-12-23): Howard Oakley:
So depending on when you run it, the installer might claim it needs 12.97 GB, 13.22 GB, or 13.56 GB of free disk space, but really wants around 14 GB.
In practice, even for the modest needs of a basic Ventura 13.0 installation in a VM, the smallest disk size you’ll be able to update from 13.0 to 13.1 is 33 GB, providing at least 14 GB of free space. To have any degree of comfort, make that a 40 GB disk with at least 20 GB free.
That’s only a start, though. Updating to 13.1 also has a long-term cost in terms of free space. Once happily running macOS 13.1, free space was around 0.5 GB less than it had been in 13.0. By the time that we reach 13.6 next summer, even that 40 GB disk with 22 GB of free space in 13.0 could well have lost sufficient free space to make further updates tight for free space.
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Apple really ought to support designating a volume for such purposes. Including removable media. If your boot drive is getting full it should be possible to plug in an SD card or USB3 drive which the OS would use for temporary file space during upgrades.
@Jon I do that often manually, because I made the partition for my recent macOS versions (where I keep older ones around as well) too small for running the macOS update. So I have the updater downloaded, then move it to another partition, and that often is enough to run the update. Sometimes not, and I have to start to remove other temp files etc.
Too bad the partition is in a place where I can't grow it any more, and that I cannot move the bootable volume to another (larger) partition any more as it used to be possible years ago.
