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.
macOS Big Sur 11.2.1 (20D75) full installer is now available for download. I've confirmed the new installer now checks for free space properly. This was a serious problem, and I'm glad users will no longer get caught by this issue. https://t.co/dYSuRjdd4p pic.twitter.com/ILxoKfhORn — Mr. Macintosh (@ClassicII_MrMac) February 15, 2021
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.
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