Can't update to Big Sur Beta 3

I had the same problem and found this in the release notes:

• Your Mac might restart but isn’t updated to a newer version of macOS Big Sur 11 Beta. (65298753)

Workaround: Create a bootable installer using the createinstallmedia command.

I'm trying to do this, created the install disk but can't seem to select it as a start up disk in System Prefs.

Got the same problem. Trying to download the full installer. However, it gets stuck after finishing downloading. (says 12.88GB of 12.88GB)

I have the same issue except I was able to get the full installer with no problems. Creating a bootable now to attempt the update that way. I'll report back with the results when this thing finishes.

(Tried both the incremental update from More Info and also the full Upgrade Now options)

I realised my issue was T2 related, I hadn't set it to enable booting from external/USB drives.

Confirmed it does indeed work from bootable media. I had to disable external media boot security and you'll need to reboot twice using the OPTION key startup before the actual BigSur beta install will begin. It takes quite a while to complete so be patient. I'm on a new Mac Pro and it still took since my previous post to complete this. Good to go now though on 20A5323l.

I've yet to get it to work/update correctly. I've

• enabled booting from external/usb drives.

• created the bootable installer on fast thumb drive.

• restart with option key

• select Install Big Sur Beta usb drive to boot from

Still on beta 2

@mm2012 - can you elaborate on "reboot twice using the OPTION key startup before the actual BigSur beta install will begin"

Would someone be able to post the terminal code to create a bootable install for the beta 3? I have it in my applications folder but getting an error when I try to manually change the code.

I was using this code:
sudo /Applications/Install\ macOS\ Install macOS Big Sur Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/SamsungUSB

Get this error: sudo: /Applications/Install macOS Install: command not found

@NickF81

sudo /Applications/Install\ macOS\ Big\ Sur\ Beta.app/Contents/Resources/createinstallmedia --volume /Volumes/SamsungUSB

you have an extra "install macOS" in the application name

So I finally got beta 3 installed. two weird issues.

When holding Option to choose boot media, it has you choose "Wireless network" - but I always have wireless off and run wired.

• I disconnected ethernet and rebooted with Option.

• selected my wireless network

• choose Big Sur USB.

next I ran into "not enough space" issue even though I had 80gb free (supposedly). found out it was Time Machine local copies. Went to terminal and manually deleted them.

Repeated the steps above and after about 30 min and 3-4 auto reboots. I'm on beta 3

I can't guarantee if was my wired vs wireless, but it never worked with wired connection and got it to work with wireless (while disconnecting the cable)

Due to the drive encryption on my device I had to fully erase and re-install from fresh using a bootable USB. Luckily with cloud storage I've not lost anything, but that's always a risk with developer software. That said, I'm now running Beta 3.

Try Commad+R, and then reinstall. Worked on Mac mini 2018.