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bige12

macrumors 65816
Original poster
Apr 6, 2009
1,473
847
Vienna, VA
I have cloned my drive storage from my July 2019 13 inch Macbook Pro to a external hard drive. I want to use that external hard drive and install macOS Big Sur on it to test it.

When I try to boot from the bootable copy off the hard drive it dose not boot,

I have the drive plugged in and hit power then hold option then select the drive I want then it goes to the apple logo and the loading bar and it gets halfway through then I see the hard drive like turn off and then my mac turn off
 
Touchbar MBPs can't boot from an external drive.
That’s not true. Macs with a T2 chip (even if they don’t have a Touch Bar) need to have the ability to boot from an external drive enabled in the Startup Security Utility turned on, but they can absolutely boot from external drives.
 
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I really want to try and get Big Sur installed on that external hard drive, so I don't mess up the main MacBook that I'm using
 
I really want to try and get Big Sur installed on that external hard drive, so I don't mess up the main MacBook that I'm using
Have you enabled external booting in the Startup Security Utility? If you have, I’d start up from Internet Recovery and reinstall Catalina to the external drive, then make sure it boots properly. Then, I’d try the beta.
 
Yes I have and the external is hard drive has catalinia on it, but I will reinstall catalinia again
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Never know when it clones it probally missed a file, this is my first time try to do this with a computer that a t2 chip
 
then now it stoped booting from the hard drive and went back to doing the samething as before, Looks like I will just probably wait til we close to the final beta and then I will install on my main daily driver
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To me iPad OS and iOS are easy to downgrade from from MacOS
 
Got it to boot from the external hard drive
What did you try? I was able to install it to a external drive through my T2 MacBook Pro. Enabled Boot from External Drive, after booting up, I get an error saying “unable to verify“.
 
I booted into recovery mode and reinstall Catalinia and it booted from it and after I shut it down and tried to reboot it did not want to boot again
 
Having the same issue with my 2019 Touch Bar MacBook Pro. I installed Big Sur over my Catalina OS on my external SSD drive. I can boot into it using a 2017 MacBook Air but not my MacBook Pro. It will stop booting and ask for the disk to be updated. When I click on update, it will continue to boot, followed by a count down and then a blank screen. This cycle will repeat until it finally boots into the Catalina OS on the internal drive completely ignoring the external HD.
 
I can get it to boot the external hard drive you just need to connect it to the internet if you the startup security on. I tried to make a Big Sur USB install, i created it and when I tired to boot it from the USB it said it need a update
 
I can get it to boot the external hard drive you just need to connect it to the internet if you the startup security on. I tried to make a Big Sur USB install, i created it and when I tired to boot it from the USB it said it need a update
I am always connected to the internet and I have all the security measures of the T2 chip turned off.
 
Trying to install Big Sur on a External Hard Drive. I made a clone copy of my macbook pro, So I can boot the USB external hard drive fine, and I log in I installed the beta profile and download the installer and when I tried to install it I get The operation could not be completed.
IMG_0319.jpeg


Then I created a USB Installer of Big Sur, and when I booted up to the installer I got this
IMG_0321.jpeg

After I did the Update then I got this
IMG_0322.jpeg


I have one more idea I was thinking about deleting the External hard drive and tried boot back to the Big Sur USB installer. What dose everyone think? Or is there anyway to fix that first error?
 
I tried about 8 times installing it to an external USB SSD. I didn't get a nice error message like you, mine just froze. Every single time. It finished the install, but booting it up, it was frozen, and a verbose boot said that there were null pointers.

I've read others being able to install to external drives, but I couldn't. I clones my drive to my external disk and installed Big Sur to my internal drive instead and that worked.

PS. I recommend creating a bootable installer, and wiping clean with disk utility making a fresh install. There are currently a few bugs associated with upgrading a system
 
I had exactly the same issue as @casperes1996

It always froze after booting to the external drive every time, ended up using the internal drive and worked effortlessly.
 
I had the same issue, I couldn't get it to boot from the external drive, it just always froze. Bypassed the update by disabling the secure boot temporarily but it still would freeze when I try to boot after installing.

Ended up installing to a separate partition on my internal drive and it works great.
 
I’m trying redownload the profile again and this time I could choose what drive I wanted to install it on before I could not choose so I’m downloading the Big Sur installation
 
i reinstalling the profile and this time it let me choose where to install it before it just skipped that and it was installed fine and now I’m downloading Big Sur installer again

UPDATE: no luck still get the BIErrorDomain error8
 
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I was able to download the installer, and tried to install to a 64gb USB3 flashdrive.
It got all the way to "less than a minute remaining"... and stayed there for a LONG time.
Wouldn't go any further.
 
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