macOS bootable external drive hangs at 1 minute left?

I'm using a Mac mini M1 2020 running Monterey 12.0.1 and want to make a bootable external drive. I tried this using a Sandisk USB 123 GB USB (3.2) and a Sandisk Extreme 1TB USB C drive. I tried it both using MacOS Recovery and the Install Mac OS Monterey app downloaded from the App Store. The process starts and seems to proceed, but "hangs" with 1 minute left, eventually times out, and the Mac mini reboots to the internal drive. Attempts to boot from the new external drive give me the error that there is an "incomplete install" on the drive. When I look at the error log during the install process, I see over 12,000 errors, too many to try to follow. How can I create the bootable drive? Thanks for your help!

Best Answered by

Jenny Zeng

Answered on Monday, April 29, 2024

Based on your description, I think you're trying to install macOS on your USB flash drive, which is not necessary if you just want to create a bootable USB installer. But regardless, you can try the following steps instead:

Step 1: Download the needed macOS installer from App Store

Step 2: Format your USB flash drive to Mac OS Extended (Journaled) in Disk Utility.

Step 3: Open Terminal and execute the following command to create a bootable installer for macOS High Sierra and later. (Replace Ventura with the name of the macOS version of your downloaded installer.)

sudo /Applications/Install\ macOS\ Ventura.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolumeFor more information, check this guide:

Complete Guide on How to Create A Bootable Installer for macOS

After the bootable drive is created, you can boot from it to install macOS on your Mac or the USB drive if you want.