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macrumors bot
Original poster
Apr 12, 2001

When upgrading to macOS Big Sur, there was an error that would cause issues if there wasn't enough storage space available. Unfortunately, the update was not checking if there was enough free space before the installation started, which could lead to data loss.


The free space issue has been addressed in a revised macOS Big Sur 11.2.1 update that was released this morning. According to Mr. Macintosh, the new update checks to make sure there is enough available storage space before installation starts.

If you don't have enough free space, the installer will say "There is not enough free space on the selected volume to upgrade the OS," and it will let you know how much additional space is required.

The new update that was released today is available only if you had not previously installed macOS Big Sur 11.2.1.

Article Link: Revised macOS Big Sur 11.2.1 Update Properly Checks Free Available Space to Prevent Installation Errors


Sep 15, 2020
Problems like this is the reason I never upgrade as soon as a new release is available.
How is this relevant? If you have enough space in the first place the install will go without a hitch. I don't even understand why people allow their system space to get lower than 35GB anyway.
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macrumors 6502a
Sep 16, 2015
Norwich, UK
Choosing storage space during purchasing is the responsibility of the buyer, not the seller. When people cheap out on storage space they are entering at their own risk.
It doesn't help that Apple has frankly been stingy on storage for years. They've only just recently made 256GB the minimum when it should have been the standard base at least 5 years ago.

Mr. Dee

macrumors 601
Dec 4, 2003
Why does an OS take up 35GB of space? I remember back when Snow Leopard cam out Apple bragged that it took less space than it's predecessor. Try trimming some of the bloat out of the next macOS release.
I’m noticing that too, it’s getting bigger in size just for the installer alone. 12 GBs is just riduclous, what kinda assets are they putting in it requiring so much space? I can understand universal binaries and so on. Considering it’s being delivered over the Internet through software update, it should be designed to download just the essential packages for the system. An Intel Mac gets what’s specific in terms of binaries for that architecture and a M series gets what’s essential for that architecture.

I hope the focus of macOS 12 is refinements, use on less drive space and just more stability.
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