Why can't I install Mac OS 26 onto external and boot from it?

[Mike Boreham]

I am trying to create macOS Tahoe USB install media on a flash drive formatted GUID and Mac OS Extended Journaled named MyVolume which a senior advisor told me to do. I want to install it on my external USB named MAC an APFS volume. Also the command isn't working

sudo /Applications/Install\ macOS\ Tahoe.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume





Password:


sudo: /Applications/Install macOS Tahoe.app/Contents/Resources/createinstallmedia: command not found

Use the excellent free MIST app to avoid syntax issues. It stopped working recently from several months but is now fully up and running.

 

[Bigwaff]

I am trying to create macOS Tahoe USB install media on a flash drive formatted GUID and Mac OS Extended Journaled named MyVolume which a senior advisor told me to do. I want to install it on my external USB named MAC an APFS volume. Also the command isn't working

sudo /Applications/Install\ macOS\ Tahoe.app/Contents/Resources/createinstallmedia --volume /Volumes/MyVolume





Password:


sudo: /Applications/Install macOS Tahoe.app/Contents/Resources/createinstallmedia: command not found

Do you have the “Install macOS Tahoe” application in your Applications folder?

 

[Fishrrman]

I second Mike Boreham's advice to try the free utility "Mist" to create the flashdrive installer.

--

Another path to try is this:
a. download the Tahoe installer file of your choice by using this collection of URL's at "Mr. Macintosh":

macOS Tahoe Full Installer Database. Download Directly from Apple!

Download macOS Tahoe full installer with one click straight from Apple! Every version of Tahoe Beta & Final available all in one place!!

mrmacintosh.com

b. I recommend you download the installer file directly onto the desktop. Then, double-click it and it should download the full installer "pkg" file, also onto the desktop.

c. double-click this installer pkg file to run it. IT DOES NOT INSTALL TAHOE. Instead, it installs the Tahoe installer app into your applications folder.

d. connect your external drive. It should be formatted to APFS, GUID partition format, and case should be INsensitive.

e. launch the installer app (in the Applications folder). Start clicking through.

f. when the installer asks WHERE you want to install, "point it" at the EXTERNAL drive. It may be necessary to enter your password once or twice to authorize this.

g. Let the installer do its job -- it will take a while.

h. When done, you should be up-and-running on the EXTERNAL drive, waiting for setup.

i. Either set up "completely fresh", or use setup assistant to migrate data from either your internal drive or another drive.

Good luck.