Apple releases bug fix for Big Sur upgrade that put Macs in boot loop

Apple has released a patch for a bug in the macOS operating system that could cause users to lose data. The new update for Big Sur checks if there is enough disk space available.

The bug emerged last week with users trying to upgrade macOS to Big Sur. In it, an error arose if users did not have enough available disk space. In that case, the upgrade was still implemented. Computers with FileVault 2 disk encryption enabled then went into a boot loop.

The Big Sur upgrade required a minimum of 35.5GB of disk space, plus an additional 13GB for the Big Sur installer itself. However, the installer did not check how much disk space was still available, so it would also start if there was not enough available space.

The only option to get out of the boot loop was to boot the computer into Boot Recovery and delete files or format the entire drive. The error was first documented by Mr. Macintosh. That says now that it has been fixed with a new update, Big Sur 11.2.1 20D75. The installer also checks the available disk space.