How to boot Studio Max from external SSD?

[Ladd]

This morning I tested to see if the external SATA SSD that was placed in an older Newer Technology hard drive dock connected to the Studio Max via USB 3.0 (and later eSATA-to-USB 3.0 cable) and was visible as a viable startup disk in System Preferences/Startup disk would actually boot the computer.

The short answer is no. The computer would emit the startup sound, then 15-20 seconds later emit the sound again and boot into recovery mode. As the external SSD was selected as the startup disk, I had to shut the computer down and power down the external SSD to get the computer to switch back to the internal SSD.

I have just received my new OWC dual-drive dock that connects to the Studio via USB-C. It is plugged into one of the front USB-C ports on the studio.

The external SATA SSD which had previously been erased and reformatted APFS via disk utility, then had the internal SSD cloned to it via SuperDuper's "erase and copy" function was placed in the dock. As before, it showed up in Startup Disk as a via option. It was selected, the computer was restarted and fully booted up.

FWIW, I erased and formatted as APFS a second SATA SSD, cloned the Mac SSD to it using the "erase and copy" function in SuperDuper and it too was recognized as a valid startup disk and did, in fact, fully boot the computer.

Given that the only difference I can see is that the external SATA SSDs are now in a more modern drive dock connected via USB-C, not USB 3.0, I'm calling this a win.

 

[MediaGary]

Late to the party here:

I had successfully created an external boot SSD (a 2TB Sabrent in an Acasis TBU401 enclosure) for the M1 Max Studio (base model) that I owned for about a month. I used the instructions for building an external boot drive found within this list of articles here:
[https://eclecticlight.co/m1-macs/] specifically (I think) the article [https://eclecticlight.co/2021/08/26/how-to-create-a-bootable-external-disk-in-macos-11-or-12/] but I can't be entirely sure.

Nevertheless, the essentials are: boot into Recovery, format the external SSD, install macOS, then boot from the external, and life is good. The follow-on is to use the Migration Assistant to push whatever apps you want onto the newly booted machine, although I chose fresh installs of all my apps. I booted from one of the rear Thunderbolt ports.

Ultimately, though, I twice had a sleep-no-wake-with-blinking-amber-light problem with the M1 Max Studio. The first time, I took it to the Apple store and they apparently re-flashed the firmware, but the trouble ticket didn't state that specifically. The second time it happened, I declared defeat, or was at least uncomfortable with continuing this pattern of failures. The failures were spaced about 10 days apart, so the FUD was enhanced by me having no way to invoke the problem, just had to wait for the Sword of Damocles.

Also, I have since learned (while upgrading my good ol' 2010 Mac Pro) that some brand/models of NVMe SSD's (e.g. TeamGroup Z330, and WD SN700) work poorly or unreliably in APFS format, but just fine in HFS+ format. I only mention that to say that it's possible that the specific Sabrent that I used was part of the sleep-no-wake problem, but there's no way to prove that without substituting a couple of other brands, and doing multi-day testing.