Its new equivalent is in the opening of Recovery Mode. M1 Macs lack the old Startup Manager, and holding the Option key during startup does nothing at all. When you want to restart from the internal disk, the Startup Disk pane is your best option. You’ll have to go through the whole process of setting your AppleID to work, negotiating two-factor authentication for this ‘new Mac’, and so on, until you can finally use your external disk fully. With AppleID and current setups, what you now effectively have is not simply another boot disk, but a whole new Mac bar the hardware. This should be relatively rapid, and at the end your Mac will automatically restart into the freshly installed copy of Big Sur on your external disk. Then select the external disk and click Continue.įollow the installation process through to completion. When it invites you to select the disk on which you want to install Big Sur, if you don’t see your external disk, click on the button to show all available disks.

Then open the Install macOS Big Sur app, and proceed. a copy of the Big Sur 11.1 (or later) installer app, obtained from the App Store via Software Update this procedure appears less reliable in macOS 11.0.1 and when installing macOS 11.0.1, so 11.1 is recommended for both.Ĭonnect your external disk, and if there’s any doubt about whether it has been freshly formatted using APFS without encryption, use Disk Utility to do so before going any further.Some suggest that if your SSD isn’t Thunderbolt, try connecting it via a USB-A port, although that doesn’t help those with MacBook Air or Pro models a Thunderbolt 3 SSD, such as a Samsung X5, freshly formatted in APFS (unencrypted) and connected to one of your M1 Mac’s Thunderbolt ports if you only have SATA SSDs which connect via USB-C rather than Thunderbolt, you may be successful, but it seems unlikely.an M1 Mac if you haven’t got one yet, I’m afraid it’s far too late for Christmas.Thanks to many comments but no real clues, I’ve now been able to solve this, and here explain how you can do this too. Last week I described how I had been unable to get either of my M1 Macs to start up from an external disk.

How do i make a startup disk for mac