Felix SchwarzJun 25, 2025

Just spent hours trying to install macOS 26b2 on an external SSD. After rebooting, it just wouldn't complete but boot back into macOS on the internal SSD eventually.

Why? I had plugged the SSD into the wrong USB-C port: on Apple Silicon Macs, you're supposed to NOT use the DFU port for this (https://support.apple.com/en-us/111336) - and of course I had. 🤦‍♂️

This document tells you which of your Mac's ports is the DFU port:
https://support.apple.com/en-us/120694

Avoid that port when installing macOS on a external drive.

Install macOS on an external storage device and use it as a startup disk - Apple Support

If you have an external storage device, you can set it up as a Mac startup disk.

Apple Support
Show threadAndy ParkJun 26, 2025
@felix_schwarz ouch. No warning either? You’re just supposed to know this beforehand?
Show threadFelix SchwarzJun 26, 2025
@thebearmaster Yup, no warning unfortunately. I'd have expected the Installer to recognize this and either warn me or even prevent me from picking the volume for installation.
Show threadAndy Park

@felix_schwarz right, I’d have expected that much.

It hurts as a long time Mac user to suspect that Apple is no longer the same company that used to pride itself in handling details like this.

Jun 26, 2025 at 1:12pmMastodon for iOS