If you’re still running Catalina or Big Sur, you’re probably now wondering whether it’s safe yet to upgrade to Monterey. While it’s not free from significant bugs yet, with the recent 12.2.1 update they’re generally tolerable, and this is a good time to assess your options if your Mac is compatible with Monterey. Don’t forget that, apart from limited security fixes, Apple only normally fixes bugs in its current release of macOS, so if you’re suffering problems still in Big Sur or earlier, you can rest assured that they won’t ever be fixed there.

First choice

For the great majority of Mac users, upgrading through Software Update or the App Store is the most straightforward to try first. Take all the usual precautions, ensuring that you have at least one, preferably two or more, complete recent backups, and have plenty of time for the upgrade and any fixes afterwards. Never rush a major upgrade: if you don’t have time now, leave until you have.

Potential problems

Upgrading from the latest security-patched version of Catalina or Big Sur is least traumatic, as your Mac’s firmware should already have been updated ready for Monterey. Oddly, though, some Macs complain that they can’t install the necessary firmware update and won’t upgrade to Monterey as a result. I explain a workaround for that below.

If your Mac is short of free disk space, you’ll need to clean up non-essentials such as snapshots; restarting it in Safe mode often frees up additional space which has been used for temporary storage. If necessary, have a good housekeeping session to release more.

Some Macs with FileVault enabled (but without a T2 chip) can run into difficulties, and prove unable to complete the upgrade. Apple’s normal recommendation then is to turn FileVault off, but some report that doesn’t appear to do anything. However, after turning FileVault off it can take a long time for decryption to complete, as it’s performed in the background, when your Mac is awake and powered from mains/AC. To check on progress with this, open the Security & Privacy pane and switch to the FileVault tab.

Alternative installations

If you can’t upgrade the standard way, there are several other approaches you can try instead.

Booting your Mac in Safe mode, with the Shift key held, is one of the recognised ways of solving macOS upgrade or update problems. Once your Mac has completed all its post-startup tasks, open the Software Update pane and run the upgrade from there.

If you have a spare USB ‘thumb’ drive, or can make a bit of space on an external disk, you can turn that into an external bootable installer disk and perform the upgrade from there. Before doing so, check again that your backups are available, in case this performs a clean install which doesn’t hook up with your Mac’s existing Data volume. If that happens, then you can use your backup to migrate from, a slower process but often more reliable.

If you opt for an external bootable installer, note that must be created on an HFS+ partition on the external disk, and follow Apple’s instructions to create the disk. If your Mac has a T2 chip, you’ll need to visit Recovery mode, open Startup Security Utility there, and enable it to start up from external disks, because that’s blocked by default.

Another way to install any macOS upgrade is through the install macOS feature in Recovery mode. Enter that holding the Option-Command-R keys and the version installed should be the latest compatible with that Mac, and not the same version that it’s currently running.

If you’re still struggling, and have an external disk which can take a basic copy of macOS, try running the macOS installer to install Monterey on that external disk, restart from the external disk, and from there install Monterey on your internal storage.

If none of these helps, contact Apple Support, who are only too keen to help you upgrade to Monterey.

Can’t upgrade firmware

Some Macs abort the upgrade to Monterey because the firmware update that’s included can’t be installed. Sometimes this is even stranger, as those Macs may already be running the correct firmware for Monterey. One workaround for this is to use the Monterey installer to install a fresh copy to an external disk: that will update the firmware as well, and should enable you to upgrade macOS on your internal storage too.

If that doesn’t work, then there’s nothing you can do apart from contact Apple Support, who may well ask you to take your Mac into an Apple store or authorised service provider for them to sort your firmware out.

Summary of installation methods

• Software Update pane or App Store as a straight upgrade;
• Safe mode, then Software Update pane;
• Make an external bootable installer disk, boot and install from that;
• Recovery mode with Option-Command-R and install from there;
• Create a bootable copy of Monterey on an external disk, boot from that, and run the installer from there; that can also fix firmware update failure.

If you do encounter problems after upgrading, try restarting, starting up in Safe mode, and resetting your Mac’s SMC and NVRAM as first resorts.

I wish you success.