crwdns2936637:0crwdne2936637:0 crwdns2853008:0crwdne2853008:0 crwdns2918746:0crwdne2918746:0
crwdns2918538:0crwdne2918538:0

crwdns2934243:0crwdne2934243:0 Dan

crwdns2934249:0crwdne2934249:0:

There are a couple of issues trying to boot from an external drive besides the systems T2 security controls.
First the drive needs to be formatted with GUID and the drive needs to be setup with APFS not HFS+ as macOS Mojave and newer requires it.
The next is the version of macOS needs to be what the system requires so you do need to make sure its setup with macOS Mojave or newer.
+
+When you start your system you do need to enable the Startup Manager to select the drive you want to boot up pressing the '''Option (⌥)''' key.
+
+Reference: [https://support.apple.com/en-us/HT201255|Mac startup key combinations]

crwdns2915684:0crwdne2915684:0:

open

crwdns2934241:0crwdne2934241:0 Dan

crwdns2934249:0crwdne2934249:0:

There are a couple of issues trying to boot from an external drive besides the systems T2 security controls.

First the drive needs to be formatted with GUID and the drive needs to be setup with APFS not HFS+ as macOS Mojave and newer requires it.

The next is the version of macOS needs to be what the system requires so you do need to make sure its setup with macOS Mojave or newer.

crwdns2915684:0crwdne2915684:0:

open