M1 mac external boot

Hello

Yes, a M1 Mac will external boot. Apparently, trying to select an external drive using the Option key doesn't work. instead, I'm having to select the external startup drive either via System Preferences or by holding down the power key during startup to get into Recovery Mode. Please note: currently, external drives cloned via Carbon Copy Cloner don't work as startup drives.

Firstly let me say that i have a 1 tb samsung ev860 in a WAVLINK enclosure that is working fine as an external on my M1 Macbook Air. I previously had a new intel mac mini which I had 3 SSD's booting Big Sur Catalina and Mojave. So I would say the issue is not with Sata drives per se. The T5 would never complete using the same method as my Wavlink Sata but after reading about the Carbon Copy method it did complete on the T5. So last night I plugged my 1 Tb Wavlink in while running off my T5

and changed the startup disk to the 1 TB. This worked fine. This morning after coming back from Costco (another $500.00 arrrg) Isay your replay about not being able to reboot with the T5. I did the same procedure and the 1Tb but the T5 would not boot. It seemed to be in an endless cycle on not completing. To get it to work again I held the power button down until it shut off and then after opening the lid quickly held the power button down again and it went into recovery mode. At this point the T5 was unplugged and i booted off the internal ssd. It booted normally. I then plugged in the T5 and went into Startup disk and changed the boot disk to the T5. Voila it booted right into the T5. So I believe with the M1 and Big Sur you must reassign your boot disk to the internal SSD, unplug the portable, boot to the internal, plug the T5, go to Startup disk,reassign to the T5 and then ShutDown. Now you can restart. This worked for me and I hope this helps others.

PS I am writing this while running on the T5

tko54321 wrote:

....create an external bootable clone connected via (apparently only) a Thunderbolt drive...

.

While not a true "clone", I have an externally bootable system with

a SanDisk Ultra 3D SATA SSD attached to a StarTech SATA to USB 3

adapter and using the Apple USB-C to USB adapter. I can clone

the "Data HD" using CCC to it and reboot without issue.

I will admit though, it was a journey and may GBs of downloading

to get there.

Putting the true "cloning" issue aside, I believe much of the adventure

involved in externally bootable systems likely has more to do with

the implementation of the TB/USB 4 ports, which seem to be creating

all manner of issues across all M1 Macs from drive compatibility to

other hardware compatibility like docks and displays. Hopefully

these can be alleviated via firmware or driver updates.

Just to review my process: that works for me:

• Format external drive (TB# with Trebleet enclosure) to APFS
• Use CCC to copy data vol to external drive
• Boot into recovery and install Big Sur on external drive. System asks for password
• the process starts and Mac reboots 2-3 times and then boots up using the external drive to finish final step of install

Is this the way you did yours? I have done this several times using my TB3 Trebleet and no issues.

I am able to boot my M1 Silicon MacBook Air from a thunderbolt 3 enclosure with a Samsung m.2 drive which has Big Sur installed on it. The external drive thinks it’s a new Mac and After set up it has everything that I have in ICloud Drive. This isn’t the most efficient way until Apple and CarbonCopy clones can get CCC to work as Itdid with the Intel macs. It is one workaround although it is not cloning you startup drive.

I have the envoy express thunderbolt 3 enclosure with internal Samsung m.2 drive inside

and using carbon copy was able to clone m1silicon data and then installed Big Sur next. Works fine bootable on M1 silicon MacBook Air either through system preferences start up disk or through options holding down the power key. Everyone seems to have different results

I have found that the type of drive is also critical. I attempted to make an external boot drive using 6 different SSD's. Some error out like others have noted and some had to be repeated 2-3 times before any success. The only one that worked every time was when I used a WD Black M.2 drive in a TB3 enclosure. The speed may have something to do with it. I also had some luck with a Samsung 840 EVO after trying 2 times before it took.

tbirdvet wrote:

I have found that the type of drive is also critical. I attempted to make an external boot drive using 6 different SSD's. Some error out like others have noted and some had to be repeated 2-3 times before any success. The only one that worked every time was when I used a WD Black M.2 drive in a TB3 enclosure. The speed may have something to do with it. I also had some luck with a Samsung 840 EVO after trying 2 times before it took.

Sounds almost like it is looking for the underlying drive technology, i.e. NVMe, m.2, etc.

when trying to boot and SATA based SSDs are seen as bad when trying to boot external on

M1 machines?

Trebleet. Purchased on Amazon. $129.99. Not cheap but is very fast when connected to the TB3 port. By the way I tried using my WD Black M2 drive in a USB-C enclosure which of course is slower than the TB3 and it would not complete the installation so speed or port compatibility may be an issue.

tbirdvet wrote:

Trebleet. Purchased on Amazon. $129.99. Not cheap but is very fast when connected to the TB3 port. By the way I tried using my WD Black M2 drive in a USB-C enclosure which of course is slower than the TB3 and it would not complete the installation so speed or port compatibility may be an issue.

Thank you so much.

I noticed that OWC has a new TB3 enclosure that is

~2/3 that cost (surprisingly). I may call or fire off an email to see

if they have tested it for booting on M1 Macs.

Just for info:

https://eshop.macsales.com/shop/envoy-express/thunderbolt-3

I noticed it as I have been checking daily for the availability

for their new TB3 hub, which should be soon if one believes

the ad. Powers a host (60 W) and gives 3 TB3 ports.

WD Black M.2. No heat sink as it will not fit into enclosure. I do use heat sink tape(provided) with the Trebleet enclosure. I just did another external drive using this setup and it works perfectly.

M1 Macs need to use their internal drive to boot--even if you can, very awkwardly, create an external bootable clone connected via (apparently only) a Thunderbolt drive. So if your internal drive crashes, your prime solution of booting from your clone is no longer possible. Apple has taken this solution away from very smart, proactive users. Maybe, perhaps, in a dream, Apple will add bootable, encrypted clones to the tasks ASR can perform.

https://www.shirt-pocket.com/blog/

[Similarly reported on CCC's site.]

MyApple8MyPC wrote:

Luposian wrote:

I love my new M1 Mac Mini, but I want to be able to boot macOS Big Sur from an external.

Until Apple fixes the flaw with the Startup Security Utility you won't be able to boot from a external.

Apple is aware of this major flaw. If it's not fixed within the next week or so I'll be forced to return my M1 and get a return.

Not being able to boot from a external is a deal breaker.

If it is going to get fixed, it will likely happen with 11.1 or perhaps a point

release which will encompass many other issues. I really doubt Apple will

release an update just for this one issue as there are still a few others to deal

with.

Also, according to Bombich Software (CCC), there is a utility that still is not

ready for cloning the protected system volume to an external drive for

the M1 which is working on Intel Macs. Perhaps it is all inter related.

If haven't already, call Apple support and have them file a bug ticket,

but make sure you get booted up to a level two or three support

when you make the call. Typically in this sort of matter, level one support

is not really useful.

Also, I think releasing a significant OS change as Big Sur (a lot of underlying/

behind the scenes things have changed dramatically) and totally new hardware

was either a bit too much or was pushed a bit too fast. Given Apple resources

and my experience as an engineer with a "marketing driven" company, I believe

the latter is true.

I found this on the Carbon Copy Cloner (CCC) Blog...

"Apple Software Restore doesn't yet support the storage in Apple Silicon Macs

In the current shipping version of macOS Big Sur (11.0.1), Apple's

ASR utility cannot replicate the startup disk in an M1-based Mac.

Attempting to do so results in an error:

'Apple System Restore Tool': Source volume format not yet supported in this version of macOS

Apple is aware of the problem and is working towards resolving it for

a future update to macOS. CCC 5.1.23 will automatically perform Data

Volume backups on M1 Macs and avoid any attempts to copy a System volume

on those Macs. When Apple posts an update to macOS that resolves the

ASR problem, we'll post an update to CCC that adds back support for

copying the System volume on these Macs."

This is the closest to an "answer" (more like an explaination) that I have found, for the problem I am having... hopefully it's resolved in 11.1, which is now (today) showing up as available for install on my M1 Mac Mini.

While further investigating this issue this morning I came across this thread

that Mike Bombich of CCC was participating.

(https://eclecticlight.co/2020/12/18/is-it-not-possible-to-boot-an-m1-mac-from-an-external-disk/)

and one of his posts stated "I can consistently boot an M1 MacBook Air from external media.

I have booted it from a Samsung T5 SSD (USB-C), a Novus Rugged USB-C enclosure with an 8TB HDD,

a Western Digital MyPassport SSD (again USB-C), and a Rocket XTRM-Q (TB3). I use the procedure that

we document here: https://bombich.com/kb/ccc5/creating-and-restoring-data-only-backups#install_macos."

But he did admit that he was getting reports from some people that his method

was not working with similar struggles that we have been seeing. Also, the fact that he got

it booting with a spinning disk HDD kind of throws out speed to the drive as

an issue. Same with the T5 which is still SATA based internally.

His opinion is "Something is not completely baked here".

I kind of agree.

BTW, the OWC folks goy back to me on the Envoy Express TB 3 enclosure

and said it was not bootable.