The MacOS Big Sur installer does not calculate the storage space required to upgrade the Mac

The process of updating the Magos Big Shrink to Magos Catalina has a big problem. In this case, the installer does not check the available disk space, which can create a hell of a cycle of installation attempts, all of which fail one after the other on the Mac to be updated.

Mr. Macintosh a pu Reproduction This behavior with the installer to go into beta 11.2 and 11.3 beta (the installer of Big Sur 11.1 may present this problem, but this has not been confirmed). This flaw does not affect intermediate updates – when moving from MacOS 11.1 to MacOS 11.2, for example – the system warns and requests free space if the disk space is insufficient. It just stops there.

The MacOS Big Summary update does not count available capacity and starts the process, updating various files until it reaches 100% of disk capacity. Beyond that, the installer will crash and restart, showing the recovery startup wizard. We see this message that there was an error while preparing the update due to insufficient storage space:

After clicking OK, this mode (different from MacOS recovery environment) allows you to select the boot size. The only problem: Macintosh does not have HD. All that remains is to close or restart the machine from the Apple menu. When restarting, the process will restart without being able to complete the Big Shrink update.

A Mac with D2 security chip, When the disk is encrypted with FileVault, Restoration method Another problem is that the administrator password of the machine is not accepted by the system. Attempting to recover password, a Emergency key Or via Apple ID, will no longer work.

To get out of this, Mr. Macintosh offers two solutions. The first is simple, but it’s very destructive if you do not back up your data before starting the update, because it’s about destroying the disk and reinstalling the system (Apple Support Sheet).

This is especially difficult for users with data stored on a Mac stuck in the installation cycle: they need to create disk space. Two scenarios arise: with or without file vault 2. If the data encryption system is enabled, you will need the help of a second Mac (under Hi Sierra or Mojave) to connect via wire (USB-C, USB-A or Thunderbolt). ) On a failed system, then use Target mode Below 10.13 or 10.14 from the Mac.

After entering the encrypted disk password, the user must delete the largest files and documents on the Macintosh HD-data disk. Once you have enough free storage on the host Mac, the Magos Big Sur installation process can be restarted and, most importantly, completed normally. If FileVault 2 is not enabled, you can use Target Mode or use an external hard drive with a bootable computer (on 2013/2017 Macs) or remove files from the terminal on the MacOS Recovery Partition.

Apple would do well to take note of this issue, which has been affecting users since the launch of the MacOS Big Sur in mid-November. In the meantime, create backups …