trying to install MacOS Big Sur on a External hard

[Jas-Singh685]

I recommend reporting it to Apple with information about your machine. Let's make it a known issue

Good idea, I'll do that! It's weird because I can boot a Catalina volume just fine using the same external drive. Perhaps a bug in the firmware that gets updated by Big Sur in relation to our machines. I'm using a 2020 13" MacBook Pro if that makes any difference.

 

[bige12]

When you download the big sur installer on the internal storage and when the computer starts can you choose what drive to install it to?

 

[casperes1996]

When you download the big sur installer on the internal storage and when the computer starts can you choose what drive to install it to?

Yes, but at least for some of us, it hasn't worked. But the option is there
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Good idea, I'll do that! It's weird because I can boot a Catalina volume just fine using the same external drive. Perhaps a bug in the firmware that gets updated by Big Sur in relation to our machines. I'm using a 2020 13" MacBook Pro if that makes any difference.

Yeah, I can too. But based on my investigations that's not what the issue is. From what I could tell, it seems like it installs fine to the external volume but that once you try booting it, the kernel attempts to locate its files on /dev/disk0 instead of the device you installed to.

I am on a 2014. Since someone else has said they have it working on an external drive, my current suspicion is that it depends on the drive interface. My external drive is a USB 3.0 SSD. it might work with Thunderbolt or something.

 

[bige12]

I just kind of afraid of doing it that way that I mention since if you can not choose then you are risking the main computer
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i just sent some feed back to apple

 

[casperes1996]

I just kind of afraid of doing it that way that I mention since if you can not choose then you are risking the main computer

Makes perfect sense. - I wouldn't recommend even starting without a backup though. Even when you can choose there's always a risk with a beta especially, that the installer didn't catch the hint. - I initially tried installing to my external SSD that didn't work as mentioned. But it was split into several volumes, and in addition to not properly installing to the volume I chose, it also nuked the partition table destroying the other volumes. Though I think that's because it got confused that I had the GRUB boot loader on there. But yeah you can choose and when I picked the external disk it didn't touch the internal one at all

 

[bige12]

At least I do have a backup of my computer drive I might back it one more time

 

[bige12]

I tried to install if from the main drive and select and still got the same error BIErrorDomain error 8.

 

[casperes1996]

I tried to install if from the main drive and select and still got the same error BIErrorDomain error 8.

Redownload, createInstallMedia, wipe drive to HFS+ (HFS+ install seemed to work better for me; Installer converts to APFS) install.

 

[bige12]

I think I will will probably do that tomorrow but I might go ahead and wipe my external hard drive

 

[bige12]

I think I finally figured it out. When you have the Big Sur installer open and selecting a drive, then open disk utilities and erase the external hard drive and I think I had it set to APFS and on the drive selection screen the drive was not grayed out anymore.

 

[bige12]

To me it seems better if you install big sur on a external with a clean install

 

[Donhugo]

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.

Same problem for me and with a 64gb USB 3 stick.
Left the Macbook all night running with same message as you.
In the morning I tried to start with the USB because the message disappeared and I suppose that finally was installed, but it freezes and does not start.

 

[bige12]

Are you just trying to install Big Sur on a 64 GB USB 3 stick, and want to boot from that to use Big Sur?

 

[Fishrrman]

RE Donhugo's reply 37 above:
I'm going to -guess- that the USB flashdrive won't boot because somehow the installer won't properly "bless" the newly-created install "as a bootable drive". I seemed to get some kind of error that suggested that.

I may just wait for the public beta in a few weeks and try again.

 

[bige12]

What I did to get around the one (BIErrorDomain error 8.). I downloaded the Big Sur installer on my main computer and when I open it I went to the drive selection screen then opened disk utility and erased the external hard drive and after I did my external hard showed up as a disk to use to install Big Sur on

 

[dwmreg]

I had to go into the Security settings in MacOS recovery. I turned the two bulleted options OFF. I left firmware password alone. The first option was regarding signed vs. non-signed OS installs and the second for allowing bootable media.
After turning all that off I was finally able to get Big Sur to install on an External Samsung T5.

 

[casperes1996]

I had to go into the Security settings in MacOS recovery. I turned the two bulleted options OFF. I left firmware password alone. The first option was regarding signed vs. non-signed OS installs and the second for allowing bootable media.
After turning all that off I was finally able to get Big Sur to install on an External Samsung T5.

Those options are relevant only on Macs with a T2 chip; But good tip for those who have T2-Macs

 

[bige12]

in the security start up I just have allow bootable usb drives, and the other security setting were left alone, I did the process above that I mention and it worked for me

 

[harriska2]

I had to go into the Security settings in MacOS recovery. I turned the two bulleted options OFF. I left firmware password alone. The first option was regarding signed vs. non-signed OS installs and the second for allowing bootable media.
After turning all that off I was finally able to get Big Sur to install on an External Samsung T5.

I take it you did this with a Mac that has the T2 chip?