I was running macOS Sierra and decided to update to High Sierra, but after updating it I notice that the file system was Journaled and I wanted it converted to the brand new APFS, so I booted on recovery mode, go to disk utilities and converted it to APFS and gave me an error after conversion related to the bootable information and basically now my Mac stays on a white screen every single time I try to boot up on the converted drive. P.D my files are intact if I connect the drive to a MacBook Air running High Sierra. P.D On beta 1 and 2 HDD it’s not supported automatically converting it to APFS.
How to Make a Bootable External Mac Hard Drive Here are the steps to create a bootable external volume to start up to on your Mac. How to Create a Second Boot Volume In order to create another boot volume for your Mac, you will need a form of external storage such as a hard drive. The faster the drive the better and a connection speed like Thunderbolt is preferred. You are going to be utilizing this hard drive, Disk Utility and MaOS installer from the App Store. If you are running the newest version of Sierra, you will be able to use the Recovery Boot option to launch your installation of MacOS to install it on your external drive. In order to boot to Recovery, restart holding Command and R.
You will then choose Reinstall a new copy of MacOS to begin the next step.
How to format your external drive for macOS Mojave. You'll need to start with a clean thumb drive or external hard drive in order to make it a bootable drive. Plug the thumb drive or cable for your hard drive into the appropriate port on your Mac. Click on Finder in your Dock to open a Finder window. Aug 22, 2018 - A bootable external or internal hard drive works well for desktop Macs but. Sierra which is the two Mac OS's used on our Mac's here at home.