Reformat & Re-install macOS Big Sur For True M1 Performance

macOS Big Sur is the first operating system to support Apple Silicon processors, e.g. the M1 chip. And it’s the first operating system outside of OS X, and overall, it’s a massive architecture change – even for Intel processors. And macOS Big Sur has not been an easy ride.

Dodgy external monitor support was the first big bugbear – on the Intel MacBook Pro it stubbornly refused to recognise the display resolutions and refresh rates and I had to unplug and replug the HDMI cable more times than I care to count. Even a DisplayPort connection didn’t amount to much – if anything, it was worse! Fixing that one took about four releases over a period of 8 months.

The other big problem was the reported figures from S.M.A.R.T that showed people’s M1 Macs’ SSDs were rapidly writing too much data, exponentially shortening their lifespan. I certainly noticed something – especially with system utilities that were running under Rosetta 2, but I didn’t believe the device’s SSD was wearing out any faster or slower than my Intel machine, or any other Mac before it. It turns out there was a problem with the kernel which Apple fixed in 11.4 and everything looked to be much better overall.

This one was fixed around the same time Apple fixed the buggy external display problem – around 8 months.

With release 11.5, Apple seemingly broke Apple Music. I couldn’t add tracks without the number of open files ever increasing until the operating system limit had been reached, causing widespread instability. Nothing fixed it – wiping the Apple Music library and starting from scratch – nothing. And it was only ever Apple Music that exhibited this problem. And it remained a problem until yesterday evening when I backed up everything, reformatted the internal SSD and re-installed macOS Big Sur 11.5.2.

Everything feels brand new, fast, clean (obviously) and works much better than it ever did before. The Apple Music open files issue is completely gone, and is the external display support better, crispier and brighter than it was before? But a question remains: what was causing the issue? Did an OS update not update/overwrite a system setting or three? If not, why not, and what is Apple doing about it?

I have rarely had to reformat and re-install macOS on a Mac – apart from selling them. To do so while I’m still using the machine is a rare sight indeed! When has macOS become Windows?! 😉

As this is was the first time I reformatted an M1 Mac, there were a number of issues that I believe were caused by my Anker USB-C dock: the first was that having skipped the Wi-Fi set-up to rely on the ethernet connection of the USB-C dock, it looks as if Apple couldn’t communicate with iCloud during the set-up. It eventually logged me in (apparently), but when it came to setting up the local user, the system hung for 10 minutes and told me that I couldn’t create the user. So I rebooted, deleted all partitions, let the Mac reboot and re-install Big Sur. I removed the USB-C dock and everything went through fine (though it doesn’t rename the HD – you must remember to do that, preferably through the Disk Utility once you’ve got a working OS again.)

I find the lack of Bluetooth support during the recovery process immensely annoying – Apple’s wireless keyboards and mice work fine, but my MX Master 3 mouse doesn’t work at all – even via a USB-C cable between the mouse and the machine.

Anyway, I am happy to have a Mac that should have been as responsive and as stable as this when I bought it earlier this year. The annual macOS upgrade with new major features is set to introduce even more bugs, and I really wish Apple could give it a bit of a rest and just continue to squash bugs – both new and regressive. I genuinely have no idea how well macOS Monterey is going to behave – but I’m planning on maybe having to reformat and re-install again at some point.