Mac Mini M1 Using External SSD

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Mac Mini M1 Using External SSD

Hi, I bought the new Mac Mini M1 and would like to use it with a external 1TB SSD. I recently bought a 2018-2019 Mac Mini and was using my external SSD just fine with it, but now with the M1 it is having all kinds of connectivity issues. I thought I would just plug it in the M1 and it would work, since it has the same OS version as the internal SSD, but it wouldn't let me. It said I needed to reinstall 11.01 all over again, so I tried, but it got halfway and then said there was an error and it stopped installing. It then said I had the wrong version of macOS, even though the internal SSD had the same exact version (11.01).

So I formatted my SSD and reinstalled 11.01 onto it. Guess what, yep, you guessed it, it says I can't use it because it needs to be "updated" - even though it is the current version of macOS (11.01).

BTW, I tried the Startup Security Utility as shown here;

https://support.apple.com/en-us/HT208198

but there was no external drive option.

How can I get this M1 to boot into the external SSD?

Posted on Dec 10, 2020 10:41 PM

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Answer 1

Dec 11, 2020 3:33 AM in response to MyApple8MyPC

MyApple8MyPC wrote:

...

BTW, I tried the Startup Security Utility as shown here;

https://support.apple.com/en-us/HT208198

but there was no external drive option. ...

FWIW, I see the same thing as you on my new MacBook Air.

There is the OS security options but no option to allow

external booting.

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Answer 2

Dec 11, 2020 8:19 AM in response to MyApple8MyPC

Your Intel Mac mini uses the Apple T2 chip and it pees on your drive on the older mini to secure and associate it with that hardware. The M1 mini also has the T2 chip and realizes that the drive belongs to another Mac, and wants you to reinstall the operating system on the drive, so the M1's T2 chip can securely mark it with its own scent.

Hardware security overview.

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Answer 3

MyApple8MyPC Author

Level 4

2,128 points

Dec 11, 2020 8:30 AM in response to VikingOSX

VikingOSX wrote:

The M1 mini also has the T2 chip and realizes that the drive belongs to another Mac, and wants you to reinstall the operating system on the drive, so the M1's T2 chip can securely mark it with its own scent.

Hardware security overview.

I thought about that too, which is why I completely reformatted the SSD and then installed a brand new fresh copy of 11.01 on it. The M1 T2 should now see the SSD as a new SSD and show the option for external drives in the Startup Security Utility, but it doesn't.

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Answer 4

MyApple8MyPC Author

Level 4

2,128 points

Dec 27, 2020 5:36 AM in response to MarcoT76

Here are step by step instructions;

https://discussions.apple.com/thread/252222611?answerId=254226490022&login=true

Let us know how it works out for you so the community knows which drives work, and which ones don't...

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Answer 5

MyApple8MyPC Author

Level 4

2,128 points

Dec 11, 2020 6:20 PM in response to woodmeister50

woodmeister50 wrote:

I tried a few times my self with the last time saying the drive needed a software

update???

Yes, when the Startup Security Utility is not set to allow external drives, it tells you to update.

The problem is it doesn't show the "External Boot" section of the Startup Security utility, so you can't select "Allow booting from external media". This is a huge bug that Apple should have known about during their beta testing of the M1.

See below what it is supposed to look like. On a M1 the lower half (everything below medium security) of the utility is completly missing.

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Answer 6

Dec 14, 2020 9:12 AM in response to MyApple8MyPC

I may have made some progress. I went back into recovery and this time it accepted my password. Previously at this step it rejected it. Once it accepted the password it installed 11.01 (even though it was already installed on the drive). Once 11.01 was installed it booted into the screen shown below, and under the icon it just said “Other...”. Then when you click on it a password field opens. The problem is that no matter what name/ password combination I use it rejects it.

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Answer 7

Dec 11, 2020 2:05 AM in response to MyApple8MyPC

Have you tried to make a bootable Big Sur flash installer via the Terminal, boot from it, erase the external device (not just the volume under it) as APFS GUID, then install Big Sur on the external disk? And you already allowed external booting by visiting the Recovery mode? Or is the external boot option missing there?? Disclaimer: I don't have M1 Mac mini, only Intel.

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Answer 8

Dec 11, 2020 12:32 PM in response to MyApple8MyPC

I tried a few times my self with the last time saying the drive needed a software

update??? Another time it stopped installing and said it could not make the

required permissions update??? One time, all seemed to go well with the install,

but it was never visible.

Installed from recovery and claimed to be 11.0.1?

Each attempt at reinstalling yielded something different. Seems this operation

is no ready for prime time on M1 Macs. I'm going to give support a call and

have them generate a support ticket.

BTW, Recovery is downloading the full installer every time! I thought an installer

would be local unless that is yet another bug.

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Answer 9

Dec 12, 2020 4:47 AM in response to MyApple8MyPC

Yep, seeing exactly what you describe.

What may be scarier is if removal of external booting on M1 Macs

is by design and not a bug and the way it will be from now on.

While I have no intension of using an externally bootable drive

on a daily basis, it has always been my Plan A if something went

awry on the main system drive and needed to get back up and running

immediately instead of waiting the 3-4 hours or more for Time Machine

to restore the system.

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Answer 10

MyApple8MyPC Author

Level 4

2,128 points

Dec 12, 2020 10:44 AM in response to woodmeister50

woodmeister50 wrote:

What may be scarier is if removal of external booting on M1 Macs

is by design and not a bug and the way it will be from now on.

I don't think that's the case, but if it were, then I know a whole lot of people with M1's that will be returning them and staying away from the new Apple Silicon machines.

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Answer 11

Peymon

Level 1

8 points

Dec 13, 2020 6:17 AM in response to MyApple8MyPC

I was using T5 Samsung and didn’t work , then I used My G technology External 1T and worked perfectly to startup externally

steps

1- hold power to get to options

2 - disk utilities and erase and partition

3 - reinstall Os from recovery.

57 min and be patient and it will work.

now I am migrating from TIme machine to new drive.

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Answer 12

Dec 13, 2020 8:29 AM in response to Peymon

Peymon wrote:

I was using T5 Samsung and didn’t work , then I used My G technology External 1T and worked perfectly to startup externally

steps

1- hold power to get to options

2 - disk utilities and erase and partition

3 - reinstall Os from recovery.

57 min and be patient and it will work.

now I am migrating from TIme machine to new drive.

Good luck. Others have reported getting as far as you

only to have it not be bootable the next time.

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Answer 13

Peymon

Level 1

8 points

Dec 13, 2020 8:34 AM in response to woodmeister50

Working just perfectly so far

just for Sh and giggles , I tried installing on

Sandisk 1t SSD and it worked as well with sane procedure as I mentioned

so my thinking is something with Samsung T5

stay Tuned

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Answer 14

Peymon

Level 1

8 points

Dec 13, 2020 1:25 PM in response to woodmeister50

Yes I did and perfectly works fine , although speed is not as fast as internal ssd

so I am planning on going to Sandisk extremes pro to speed it up

but , speed list is Negligent , but since I have working after 3 days of calls and working on this

at times it feels like waiting for paint to dry ;)

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Answer 15

Peymon

Level 1

8 points

Dec 13, 2020 1:30 PM in response to Peymon

Sorry some missing ( speed loss is)

since I have it working after three days of talking to Apple techs and reading

answer was always in front of me try another drive and that did it

so , Option disk choice or Startup disk in System Pref

both will do

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Mac Mini M1 Using External SSD

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