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Unable to install macOS Big Sur Beta 3 on Mac mini
- Thread starter symphony
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I have the same problem as well I have been trying to install sense yesterday no go! So disappointed
In my experience, you have to make the USB installer and boot from that device to successfully install the update. Make sure you boot to recovery mode using Command + R on boot to disable T2 chip security (allow booting from external drive and perhaps lower OS verification to medium or off temporarily). You should be able to find the instructions to make a USB installer on Apple’s website. Just replace the Catalina text with the name of the Big Sur Beta installer. When all of this is done and you’re ready to install boot the Mac mini while holding the Option key to select the boot device. Should be the one that looks like a drive icon and labeled macOS installer.
I got it successfully installed! Boot into recovery mode and selected fresh install and from there it downloaded b3 and installed. It took around an hour but all works great and no need for me to make a usb boot installer. Why I don’t know 🤷🏻♂️
No it doesn’t you just choose to recover your Mac it went really slow between loading screens. Sorry just trying to remember off the top of my head ( have weekend on my 🧠)
[automerge]1595617015[/automerge]
Hold on boot up Command+r for a awhile until it gets into the recovery screen
It worked. Thanks so much!
My Macintosh HD was locked, probably because of FileVault. Unlocking it in “Reinstall macOS” doesn’t work, I had to mount it in Disk Utility before I could reinstall.
I’m glad it worked one way or another have a great weekend ✌
This is actually mentioned in the Developer Release Notes. I had to resort to a USB Stick.
√ Thanks—I followed your advice and now have a 16GB flash drive with 'Install macOS Big Sur Beta' ready to go. I've gone into StartUp Security Utility via Recovery Mode boot and turned everything off to allow my T2 to install. I've also turned of FileVault.
X The drive is fit and well according to Disk Utility's 'First Aid' and it begins to install Bug Sur on my MacBook Pro; but on my Mac Mini it gets stuck. I begin in System Preferences, and change Start Up Disk to the BS flash drive. Reboot. Installation looks good ( logo and progress bar). After a while I get "A software update is required to use this disk". I allow this update, then I get a new error message: "An error occurred installing the update".
Do you have any idea what this is or how to fix it? I assume that there's something about the T2 chip that's not allowing it but, as I say, I've given permission to boot from another drive.
BACKGROUND: This is a 2018 Mac Mini, which keeps crashing. This post [https://forums.macrumors.com/thread...fter-security-update-2020-002.2228812/page-10] thinks that Big Sur will force BridgeOS to update and cure my kernel panics.
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I have the exact same problem with my 2018 Mac mini. The latest Public Beta 5 would not install.
That's my guess, too. But I don't know what to do about it.
I had the same issue on my 13" 2018 MBP. The fix was to re-flash the bridge OS using a USB-C cable and another Mac.
Previous to this I had tried everything including a full reformat, clearing NVRAM, clearing SMC, re-downloading Big Sur, USB thumb drive install. Nothing worked until I used configurator and re-flashed the bridge OS.
Thank you for the suggestion.
I looked at the instructions here: https://mrmacintosh.com/how-to-restore-bridgeos-on-a-t2-mac-how-to-put-a-mac-into-dfu-mode/
Holy cow! It is not an easy process.
it’s because mac mini 2018, as iMac 27 5K 2020, both have T2. the chip protect from install any beta software. I know cz I have both. luckily I avoid repeating same error on the brand new mac mini, but I have still the iMac 27, also brand new, blocked in a stupid loop. you need to take the mac mini to Apple and with Apple Configurator Beta 2, yes, beta, they will restore the os, witch, btw, will be reinstalled completely from scratch.
I don't know if that's entirely true. I had no problems installing Catalina beta on my Mac mini.
This is incorrect. Apple has not yet released a beta which supports the 2020 iMac, but every other computer Apple sells which has a T2 can install the Big Sur betas.
Update: Just tried to install and it took. Didn't do anything different (same installer as yesterday), I am guessing the error it was throwing about BridgeOS being out of date was Server Side and it was fixed between yesterday and today?