Why macOS updates can block your Mac and what to do about it
Anecdotal reports from the weekend suggest that the macOS Monterey update may block some Macs during installation and the machines become unresponsive. MacRumors has compiled a representative set of complaints from the Apple Support Communities forums and Twitter that describe largely the same symptoms: unresponsive Macs that cannot be resuscitated with the typical SMC and NVRAM diagnostic catchalls.
The reports summarized by MacRumors mention several Intel Mac models ranging from model year 2015 to 2020, but don’t mention Apple Silicon models – this makes sense as they update a bit differently than Intel Macs and may not be prone to the same issues .
We asked Apple about these anecdotal reports to see if the company was aware of any issues or if there were any indications for people whose hardware stopped responding to input after a software update. We also have our own recommendations as well as some hypotheses as to why these major updates sometimes cause more than usual numbers of hardware problems.
macOS updates don’t just update macOS
When Apple releases new macOS updates, you don’t just get updates for the operating system. Since around 2015, Apple has also been distributing most firmware updates as part of the operating system rather than separately (this includes updates to the “bridgeOS” software that runs on Apple T1 and T2 Macs). For PC owners, imagine Windows updates that might also update your computer’s BIOS or graphics firmware.
This saves end users from having to take steps to take advantage of firmware-level security and feature patches by simply keeping their software up to date. Apple’s firmware patches include mitigation for hardware-level vulnerabilities like Specter, Meltdown, and the like, and Apple has also released updated firmware with macOS High Sierra to add APFS boot support to older Macs.
But bundling firmware updates also increases complexity. If your Mac is disconnected or the battery is dead during a firmware update, it may fail to start and cannot be revived using standard methods. And because they are more intensive and take longer than a typical software update, both firmware updates and major operating system updates can occasionally reveal underlying hardware problems with RAM, memory, or other components.
How to fix (and try to avoid) these problems
Apple T2- and Apple Silicon-based Macs can be put into DFU mode and their firmware restored from a second Mac using Apple Configurator 2.
If you’re using an older Intel Mac with no Apple T2 chip (most Macs shipped before 2018) and resetting your SMC and NVRAM on your computer won’t do anything, the best thing to do is to contact Apple, either on the phone, via chat or in an Apple Store. If the real underlying problem is your hardware, they can fix it (although it can cost you if the warranty is out). Otherwise, they will have more tools to diagnose and revive your machine.
If you’re using an Apple T2 and have another Mac available, you may have another option. These Macs can be booted into a “DFU” recovery mode, similar to iOS devices and Apple Silicon Macs. Following Apple’s instructions, you can connect your “bricked” Mac to a second Mac using a USB or Thunderbolt cable and restore the firmware using the Apple Configurator app. If the Mac is bootable after the firmware is restored, you should be able to use Internet Restore or a USB installation drive to start a fresh installation of macOS on the system. Apple Silicon Macs can be restored in a similar way.
If you use the “Revive” option in the configurator app, an attempt will be made to restore the firmware without touching the data on the drive. If that doesn’t work, you can try a complete wipe and restore at the expense of all of the data on your Mac’s internal hard drive. If you keep decent backups, it pays to get your computer up and running again. If your Mac has vital data stored on it and nowhere else, or if DFU recovery is not working, the next step should be to contact Apple.
The best way to avoid problems is to not update your Mac until Apple has released some major bug fix updates for Monterey, which usually makes sense with any new software release, whether there are widespread problems or not . Apple’s security updates for Catalina and Big Sur often contain the same firmware updates as the new operating system – this is required to patch firmware-level vulnerabilities may not help. But assuming the problems are caused by a combination of new firmware updates, hidden underlying hardware problems on individual Macs, and a new major OS update, staying on Big Sur or Catalina for a few more months can remove at least one variable from it Equation.