
Any of these drives can be made into a macOS bootable drive with macOS Tahoe. Here’s how.
The SSD storage that Macs now all use is dramatically less likely to fail than spinning hard drives were, so you may never need to start up from an external drive. Only, that booting from an external drive used to be a life-saver if your Mac wouldn’t start up, and now it can only be that if you have taken certain steps in advance.
That’s because while an external startup volume is a help to you with diagnosing problems or just getting on with your work, it’s a potential security risk. Anyone with a drive could, in theory, boot your Mac and gain access to the data on your internal storage, or connected drives.

