How to create a bootable MacOS Sonoma USB drive? (M3 MBA)

[swealpha]

Hello guys!

How do you create a bootable usb drive with a fresh installation of MacOS Sonoma that is possible to run with a M3 Macbook Air?

I am kinda newbie, but i managed to create a MacOS Sonoma installer on the USB drive. But when I try to install it on the same usb-volume it dont work. So I created 2 volumes and tried to install from the USB-sonoma installer to the other APFS volume, but that didnt work either to boot.

Everytime i try a "new" solution i need to wait about 55 min for the installation to finish...

I would be really really thankful if someone know a solution that works.

Thank you and wish you all the best.

 

[jdb8167]

You might start here: Make a Ventura bootable external disk for an Apple silicon Mac

 

[swealpha]

You might start here: Make a Ventura bootable external disk for an Apple silicon Mac

The computer comes with MacOS Sonoma not Ventura. I dont know if that makes any difference :/

EDIT: Following the steps now, lets see what happens. 😬

 

[swealpha]

Nope, it dont want to boot from the USB drive. ;(

Maybe it is because I have another partition with timemachine on it on the same usb drive.

 

[swealpha]

I downloaded Mac OS sonoma 14.5 and choosed the installation location as the external ssd APFS. Just like this:

But it didnt boot either. Gah.

 

[kitKAC]

How exactly isn't it working?

 

[swealpha]

How exactly isn't it working?

When choosing to boot from the external SSD in MacOS settings it says "The macOS version on the selected disc must be reinstalled." Just normally hold the power button and choose to boot from the external SSD dont work either.

Maybe because my computer is MacOS 14.4.1 and the usb MacOS 14.5?

I choosed APFS GUID.

 

[kitKAC]

Do you want to reinstall Somoma on the internal SSD or put it on an external one to boot off? Your first post sounds like the former.

 

[swealpha]

I want to install MacOS Sonoma to a external SSD. And then run the computer from the external SSD.

This is the error i get when trying to boot from MacOS Sonoma installed on a external SSD.

""The macOS version on the selected disc must be reinstalled."

 

[swealpha]

It seems like the issue could be the external Samsung T7.

Alot of people having the same issue:
https://www.reddit.com/r/MacOS/comments/10rf0z8 even Bombich has writed about it:

External Boot Troubleshooting | Bombich Software

bombich.com

 

[Fishrrman]

First:

Use an external SSD (NOT a platter-based hard drive) for this job.
HDD's simply aren't fast enough any more.

The SSD should not be used for anything else EXCEPT the bootable drive (i.e., don't "share it" with a tm backup, etc.).

Re the reported problems with the Samsung t7 and t7 "Shield"...
I've seen some eccentricities with the t7 drives -- specifically, write speeds can be dead slow (like 2-4MBps) when running speed tests on them. These can be remedied, at least for backup and data drives, but might affect how a drive runs at boot.

For an SSD that seems to work fine as an external boot drive, I've been using a Crucial x9 (1tb).

Or, get an nvme "blade" SSD and the USB3.1 gen2 enclosure of your choice, and make your own.

OK, having said that...

If you're using an m-series Mac, I suggest that you use the free utility called "Mist" to both download the OS installer AND create a bootable flashdrive, all in a single operation. Get Mist here:

Release 0.10 · ninxsoft/Mist

Mist now ships logs to the unified logging system! You can view the Mist Log window via the: ⌘ + L keyboard shortcut Mist > Window app menu Show Mist Log toolbar button Logs can also be monitor...

github.com

(you want the "dmg" file)

Use a USB flashdrive 32gb or larger.
NOTHING smaller.

Erase the flashdrive to "Mac OS extended, journaling enabled, GUID partition format".
DO NOT erase the flashdrive to APFS.

Now open Mist, locate the OS version, and let it build the flashdrive installer.

Once the flashdrive is created, boot the m-series Mac from it.

If it opens to the installer, QUIT IT for now and open disk utility.
We need to prepare the SSD.

IMPORTANT: Go to the "view" menu (disk utility) and choose "show all devices".

Look at the list on the left.
Locate the SSD, and click on the top line (for the SSD) that represents the physical drive itself.
Erase to APFS, GUID partition format.

Quit disk utility and open the OS installer.

Start clicking through and when asked where you wish to install, select the external SSD.

Then let the installer do its job.
It will go through several reboots, and the screen will go dark for a minute or more with no other indication of activity. Just be patient, it takes a while.

When done, when you see the initial setup screen (choose your language), decide whether you're starting "completely fresh" or want to migrate from a backup.

If you're migrating, connect the backup NOW and go on.

Good luck.

 

[swealpha]

Thank you but i found the solution!
You must use the right USB-port. Not the left one.

Cannot install macOS Sonoma to an external SSD on MacBook

I want to install macOS Sonoma from my M3 MacBook Air which runs Sonoma as well on the internal storage. My goal is to install a second OS to an external Samsung T7 SSD and then run the computer fr...

apple.stackexchange.com