Cannot install macOS Big Sur Beta | Apple Developer Forums

Aug ’20

The "fix" is to restore BridgeOS on the T2. This can be done using a 2nd MacBook that has a USB-C port, downloading Apple Configurator 2 software and connecting the 2 laptops with a USB-C cable. The MacBook that needs restored has to be put into DFU mode. It's useless to take it to a Genius Bar. All they will do is keep it for 6 days and run diagnostics on it. If you can't do this yourself, you should just wait until Big Sur final is released. Hopefully by then the issue will be resolved

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RobChag OP

Aug ’20

I can confirm that restoring (or rather, reviving) T2 BridgeOS resolves the issue.

I shall note, however, that restoring T2 BridgeOS is delicate and risky procedure. I personally had no issues whatsoever, but I've read multiple reports of failed procedure resulting into bricked hardware. If anything goes wrong, it guarantees a trip to Apple service as there's no DIY solution available.

If that's your only or your main machine I strongly recommend waiting for subsequent build or even the GM where this issue will most likely be fixed by Apple.

This being said, detailed instructions on reviving or restoring the BridgeOS can be found here: https://support.apple.com/en-gb/guide/apple-configurator-2/apdebea5be51/mac

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Phenix84 OP

Aug ’20

I used the solution suggested by macguy59 and RobChag, it solved the problem with the error at 12 minutes of installation, but after the initial installation, the system asks to restart the PC, I get an apple, the installation starts, the screen blinks and boots normally in the OS Catalina, tried to put on a clean Catalina OS, the problem persists.

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Archetyp OP

Sep ’20

Today I succeeded in installing MacOS Big Sur 11.0 Beta (20A5354i) on my MacBook pro 16".

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ayoj4s11 OP

Sep ’20

The public beta is working now. Will try the developer beta as well.

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billxiong OP

Sep ’20

I've met this problem last week. I had my 2018 MBP repaired and after it was returned, I could not install Big Sur beta5 anymore. I tried to reset SMC PRAM, all failed. I've called Apple's developer support and Apple customer support, they all said the they do not support any Beta system. Then I saw this post and thanks macguy59 and RobChag's solution, I recovered the firmware of T2, after long waiting for network recovering, now I finally installed Beta 6 on my MBP! Thanks a lot!

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defblox OP

Sep ’20

I have everyone's answer. I couldn't find the answer in any forum at all so I came back to post the solution.

I recommend starting with a fresh Catalina install, but I don't think it's necessary.

Next, make sure you decrypt your hard drive. Then follow the normal process to install Big Sur Beta. I did the latest build.

I am on a MacBook Pro mid 2015. Was running Catalina.

The whole update took a few hours after download. Encrypt your hard drive again once you are running the new macOS.

If you have any questions, let me know.

***EDIT: If you screwed up your system, no worries. Make sure you are connected to the internet and run Command P to install a fresh copy of the original OS your Mac had. Then once you have a fresh install, follow the normal steps to do the beta install.

I had previously tried all the refresh of PRAM etc etc. This is the only thing that works.

1

forzabucks OP

Sep ’20

Just had this same problem re freezing at 12 mins. Confirming other reports. Fixed by turning off FileVault (then decrypting, which took hours).

Then restarted my computer.

Then reinstalled Big Sur and everything worked fine.

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A_Mac_User OP

Nov ’20

Yes! Apparently doing first aid in recovery mode(restart the computer but hold Command+A)and then turning off firewall solves the issue. Hope this helps!

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GrantMeStrength OP

Nov ’20

I had a terrible time trying to install previous Betas - invariably it went wrong at some stage and I needed to re-install everything from scratch. This time it worked. I did two things differently:

I made sure there were no kernel extensions installed. This meant removing the SOPHOS antivirus program I had to install for work.
I booted holding Shift (whether this actually does use a "safe mode" or is a superstition I don't know any more :-)

The installation of the Beta then went smoothly. Good luck!

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InkLondon OP

Nov ’20

Same issue here. Mac mini 2018 running Catalina 10.15.7.
Same issue at 12mins when trying to upgrade to Big Sur RC2.

This is going to be a big problem for Apple if they release this like this.

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FarisFX OP

Nov ’20

Same issue here.fully loaded 18 core iMac Pro running Catalina 10.15.7. when trying to upgrade to Mac OS Big Sur RC2.
at the 12min mark the installer errors out stating

"An error occurred installing macOS. You can try again to complete the installation".

How exactly are they releasing this tomorrow?

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FarisFX OP

Nov ’20

Same issue here.fully loaded 18 core iMac Pro running Catalina 10.15.7. when trying to upgrade to Mac OS Big Sur RC2.
at the 12min mark the installer errors out stating

"An error occurred installing macOS. You can try again to complete the installation".

How exactly are they releasing this tomorrow?

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scb OP

Nov ’20

having his issue with RC2 released last night. 16in MBP

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GianniV OP

Nov ’20

MacBook Air 2020 13'' - Running Catalina 10.15.7:
Having the same problem at 12 minutes.
Also, I created an USB for fresh install, but it stop and says: "to use this boot disk you need an update", I click on "update", but the problem persists.
No way to install Big Sur.
I tried the suggestion to reset the NVRAM, I tried also to stop FileVault. The only thing I haven't tried is reset of SMC.
I don't know how tomorrow they can officially release.
I tried to run the fresh install from USB in another MacBook Pro (2015), and there it's run.

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D1mers0n OP

Nov ’20

MacBook Pro 16" 2019
The same problem at 12 minutes.
Unfortunately, disabling FileVault isn't help for me. I also tried safe mode, redownload Big Sur installer, etc. Upset and wasted time.

I deleted the developer profile and will try the official release tomorrow, but not sure if they fix it in 1 day.

I also noticed that Big Sur has disappeared from the Beta Software Downloads in the last hours.
(Update) It's appear again.

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Karad0 OP

Nov ’20

Same Pb in MB pro 16 2019

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Powderworker OP

Nov ’20

Same issue here with a MacBook Pro 13" 2020.

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kh4inguyen OP

Nov ’20

I got the same problem here. Tried everything: Reset NVRAM, Reboot, Clean install Catalina then try again, boot from external disk, turn of FileValt, Firewall.....

And still got stuck at 12mins. MacBook 16 2019

1

apoc527 OP

Nov ’20

Same here. MBP 15" 2018. Tried all the SMC, NVRAM, Safe Mood boot, etc. All with dev beta profile. Trying the public beta profile just for fun.

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Amxzingly OP

Nov ’20

Also want to try it out for fun. 2018 MBP, 13” 512 SSD w/ 8GB

Same message just at the 12 min mark.

Edit: Just tried again and noticed a jump from 12 minutes to 10 minutes right before the error message.

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Nugget OP

Nov ’20

Same issue here on a MBP 16" with Dev RC 2. Same symptoms as everyone else.

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Apple4Days OP

Nov ’20

Same issue here, jumps from 12 to 10 minutes. Will try reviving the T2 chip when the USB-C to USB-A cable comes in on Friday (hopefully the public release tomorrow will fix it).

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JerryJnr OP

Nov ’20

Same problem here MBP13 2020

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rockbmi OP

Nov ’20

Same issue here, 16" MBP. I have also Restored the firmware on the Apple T2 Security Chip and still getting the same error.

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