For nearly 12 minutes, the progress bar was stuck at 98.6% complete and “about 5 minutes remaining”, and on many older Macs those lasted even longer. Did the update get stuck?
softwareupdated
Why isn’t the progress bar for macOS updates better? Why can’t it estimate the whole time remaining to complete an update?
How a Content Caching Server can be used to supply an update. Preflight checks are extensive, and lead on to other preparation. Finally the boot chime is muted, and the Mac rebooted to allow installation.
How Software Update settings obtains a list of available updates, and the variants that should contain. How mobile asset catalogues are checked, and preparations made to download the update.
Software update was completely redesigned for Big Sur, using finite state machines to enable reliable, flexible and robust updates to be applied to macOS. These are documented in log entries made during an update.
How macOS 26.2 updated to 26.3, variation in download sizes, how macOS works out free space requirements to proceed with the update, and its sequence of stages run by a finite state machine.
At 18:00 on 16 September, XProtect 5315 was released for all Macs. Sequoia systems were unable to update for 24 hours, and Tahoe silently updated when it felt like it. How come?
There should be an update available, but you can’t find it, or it fails to install, or you have problems with a Content Caching Server. How to tackle these.
Opening the settings runs a partial check for updates, but omits important updates, and almost immediately loses its help button.
The Eclectic Light Company 