M1 Macs, boot from external drive possible?

[pistonpilot]

I know this happened to pistonpilot here but it is not something I have seen reported elsewhere by people who have successfully booted M1 Minis. I have an M1 Air so everything I do is through the USB-C ports.

I created the OS installation on USB A. My connector on the SSD is USB C.

I booted several times on USB A and then tried USB C.

It worked until I woke up the next morning to find the system locked up. I had to shutdown with power. It never booted again from the SSD external. I can use the SSD external and I migrated my settings and Library but no files from the external SSD to the internal SSD on the Mac Mini.

I am able to choose the external SSD to boot, but it won't complete. I am using it now as data storage. It has a full OS on it, so I expect to be able to boot my iMac (out for repair) from the external SSD with no issues.

Apple has not admitted to either a Big Sur issue or an M1 issue.

 

[pistonpilot]

I don't understand this. What kind of apps need so much space on the boot drive that you have to boot from an external? Will even a 2TB internal not work for these apps?

I don't understand your not understanding. I bought a 256gb SSD Internal/ 16GB Mac Mini for my son. I expect to be able in an emergency to boot my external OS which I use on my iMac on the Mac Mini at a moment's notice.

Why is that difficult for you to comprehend?

I have every reason to think that this is possible.

 

[ThemePro]

I installed Big Sur to an external Thunderbolt SSD and no problems booting up on my M1. I found some good instructions in an article titled, "How to boot an Apple Silicon Mac from an external drive" by Malcolm Owen - google as needed.

 

[pistonpilot]

I installed Big Sur to an external Thunderbolt SSD and no problems booting up on my M1. I found some good instructions in an article titled, "How to boot an Apple Silicon Mac from an external drive" by Malcolm Owen - google as needed.

Helpful but not entirely helpful. I fail to understand why you didn't provide the link to Malcolm Owen's page. I will provide it.

How to boot an Apple Silicon Mac from an external drive | AppleInsider

If you have bought an Apple Silicon Mac or MacBook but need to upgrade your storage without buying a brand new device, you can set up your Mac to run from an external drive. Here's how to boot macOS Monterey using external storage on the new Mac lineup.

appleinsider.com

Your "solution" is only a solution for those with a pure Thunderbolt drive. It is of no use to me having an Extreme SSD with a USB C connector, or a USB A connector.

I should be able to boot all three.

 

[Mike Boreham]

I don't understand your not understanding. I bought a 256gb SSD Internal/ 16GB Mac Mini for my son. I expect to be able in an emergency to boot my external OS which I use on my iMac on the Mac Mini at a moment's notice.

Why is that difficult for you to comprehend?

I have every reason to think that this is possible.

I can well understand that 256GB internal needs an external drive, but not that you have to boot from the external. I agree you could choose to have a big external and boot from it but not that you have to. You can boot from the internal and have all the data and media on the external. My own iMac is only 256 GB so I make a lot of use of externals but not to boot from. I accept you want to be able to boot from an external in an emergency, that is different.

BTW you will not be able to boot an Intel iMac and an M1 Mac from the same actual external installation. They are different. I have tested it both ways round. An install done on Intel will not boot an M1 and an install done on an M1 will not boot an Intel mac. Some more discussion on this In this thread.

 

[pistonpilot]

I can well understand that 256GB internal needs an external drive, but not that you have to boot from the external. I agree you could choose to have a big external and boot from it but not that you have to. You can boot from the internal and have all the data and media on the external. My own iMac is only 256 GB so I make a lot of use of externals but not to boot from. I accept you want to be able to boot from an external in an emergency, that is different.

BTW you will not be able to boot an Intel iMac and an M1 Mac from the same actual external installation. They are different. I have tested it both ways round. An install done on Intel will not boot an M1 and an install done on an M1 will not boot an Intel mac. Some more discussion on this In this thread.

I will be very dismayed if I cannot boot from my external Sandisk 1TB Extreme now that it is created on the Mac M1 Mini.

That would suck.

As to wanting to do this, I want to be able to boot from either interchangeably. The external SSD is faster than the Fusion drive in my iMac. It may be moot as the repair on my iMac is drifting towards 14 days. When it hits day 15, that is an automatic replacement of my 1-year-old iMac thanks to Applecare.

If they replace this iMac, it will be my fifth consecutive replacement since 2008 when I bought my first 21 inch iMac.

The new replacement will come with an SSD.

I should be able to boot Big Sur on either device, Intel or M1. I have ways around the issue.

 

[Mike Boreham]

I will be very dismayed if I cannot boot from my external Sandisk 1TB Extreme now that it is created on the Mac M1 Mini.

That would suck.

As to wanting to do this, I want to be able to boot from either interchangeably. The external SSD is faster than the Fusion drive in my iMac. It may be moot as the repair on my iMac is drifting towards 14 days. When it hits day 15, that is an automatic replacement of my 1-year-old iMac thanks to Applecare.

If they replace this iMac, it will be my fifth consecutive replacement since 2008 when I bought my first 21 inch iMac.

The new replacement will come with an SSD.

I should be able to boot Big Sur on either device, Intel or M1. I have ways around the issue.

You have had bad luck with your iMacs ! I have only ever owned one iMac, the one I have now, which has been solid since I bought it as an Apple refurb three years ago. It would be good if they send you a replacement with an SSD.

If my iMac had a fusion drive I would probably also choose to always boot from from a fast Thunderbolt external. (Thunderbolt is better than USB for a daily use external boot as the system sees the TB external as equivalent to the internal, which is not true for USB).

 

[pistonpilot]

You have had bad luck with your iMacs ! I have only ever owned one iMac, the one I have now, which has been solid since I bought it as an Apple refurb three years ago. It would be good if they send you a replacement with an SSD.

If my iMac had a fusion drive I would probably also choose to always boot from from a fast Thunderbolt external. (Thunderbolt is better than USB for a daily use external boot as the system sees the TB external as equivalent to the internal, which is not true for USB).

No, I have not. Apple hardware is crap. I have averaged a new iMac courtesy of Applecare every three years. They fail way too much. Mac Minis are reliable, iMacs are not.

 

[matsuda0707]

Today Big Sur 11.2 was released, and I tried to create Big Sur on the external USB drive (USB-C connected).
The installation, initial setup and startup on external USB-C drive successfully completed, and switch between internal and external disks became uvailable.
I confirmed this on my Macmini 2020 (M1) with 16 GB RAM and 256 GB disk.

I summerize my experience;

1) external disk on USB-C
previously (Big Sur 11.1) could create Big Sur on it, but can not switch to external disk! ---> Now it can be created and switch to it and runs normally!
2) external disk on USB-A
previously (Big Sur 11.1) could create the last Big Sur 11.2 (RC3) and switch to new disk. ---> Now can not switch to the Big Sur 11.2 (RC3)! I can not use Big Sur 11.2 (RC3) anymore!
3)Thunderbolt
previously I confirmed the creation and activation the external disk on Thunderbolt. But now I did not check it because teh thunderbolt port is used for other purpose. It may work and should work.

After updating to big Sur 11.2, USB-C became available, but USB-A became unavailable!!!
Very strange issue!

 

[jdb8167]

Today Gig Sur 11.2 was released, and I tried to create Big Sur on the external USB drive (USB-C connected).
The installation, initial setup and startup on external USB-C drive successfully completed, and switch between internal and external disks became uvailable.
I confirmed this on my Macmini 2020 (M1) with 16 GB RAM and 256 GB disk.

I'll have to try again later tonight. This afternoon is shoveling snow after watching (hopefully) the SpaceX Starship SN9 test flight.

 

[pistonpilot]

And more bad news from Apple Engineers: You cannot boot a disk created on Intel on M1 and vice-versa.

More crap from Apple.

 

[Mike Boreham]

Not news, More about this in this thread.

 

[Mac... nificent]

My solution yielded a working external drive for 12 hours and then it would no longer boot. Apple, you suck.

I have officially renamed Big Sur to Big Sour.

Apple hasn't even posted anything telling what will, and won't, work so everyone is just shooting in the dark

 

[Mac... nificent]

And more bad news from Apple Engineers: You cannot boot a disk created on Intel on M1 and vice-versa.

More crap from Apple.

Why, exactly, is that "crap"?

You can't use a hard drive that's formatted in PPC or Windows either. M1 is a totally different animal from intel. A specialized format system is needed and to be expected.

 

[winna]

To you all, external boot on M1 HAS TO BE THUNDERBOLT 3 or NO GO!

 

[Mike Boreham]

To you all, external boot on M1 HAS TO BE THUNDERBOLT 3 or NO GO!

I can boot from a Samsung T5 USB. So can Mike Bombich maker of CCC with whom I had a support ticket on the subject. Also see earlier posts by others in this thread.

 

[Mac... nificent]

To you all, external boot on M1 HAS TO BE THUNDERBOLT 3 or NO GO!

Not true. USB is supported with the Apple USB-C to USB (MJ1M2AM/A) adapter.

The Sandisk Ultra 3D SATA (needs a sled) and the Samsung T5 V-NAND USB 3.1 External have also been tested and are supported.

The Startech USB 3.0 251BMU313 Enclosure is also supported.

 

[gogogo2]

After Reduced Security, usb external ssd and typec ssd both can boot,

 

[Mac... nificent]

After Reduced Security, usb external ssd and typec ssd both can boot,

The problem is that many can't select reduced security because Big Sur will give them error messages....

 

[gogogo2]

The problem is that many can't select reduced security because Big Sur will give them error messages....

Reduce security on internal ssd first, then install big sur on external ssd in recovery, m1 will boot from external ssd,

 

[Mac... nificent]

Been there, done that, it just gives errors...

 

[gogogo2]

You boot from internal ssd first, turn off Mac , then reduce security again,

 

[Mike Boreham]

After Reduced Security, usb external ssd and typec ssd both can boot,

Reduced Security is NOT required, nor is a USB-C/USB-A connector (at least on my M1 MBA)

See this thread.

 

[gogogo2]

Reduced Security is NOT required, nor is a USB-C/USB-A connector (at least on my M1 MBA)

See this thread.

After reduce security, any usba usbc external ssd was able to reboot for M1,

 

[Mike Boreham]

After reduce security, any usba usbc external ssd was able to reboot for M1,

As I said in the other thread, there are situations where reduced security is required to boot an external, but making a bootable external and booting from the same mac is not one of them....in my experience.