Instead of the completing the installation, my computer just booted up using the OS on the internal drive. I then designated the partition on the external hard drive as my destination for the installation.Įverything seemed to go fine until the installer rebooted my computer. I rebooted with both the bootable USB installer and the external drive plugged into USB ports and selected the bootable USB installer as my startup drive. Using Disk Utility, I created a Mac OS Extended (Journaled) partition on the external drive as my destination for the installation. I created the bootable installer using the instructions here. (I got the 5.2 GB Install macOS High Sierra application here.
I created a bootable USB installer for High Sierra. The computer I'm using is running Mojave, however, so it won't run the High Sierra Installer. I am trying to install High Sierra on an external disk. I'll try to keep this as simple as possible but it's a little complicated.
