Can't update Big Sur from beta 2 to beta 3

I have both a Mac Mini 2018 and a VMware (preview build 16530630) system with BS Beta 2 (20A4300b) running.

Both offer the beta 3 update, even both the universal installer with 12.9 GB (which I used successfully to update the DTK, where I didn't get the automatic update offered yet), and the Intel-only installer with about 5-6 GB.

I tried to use both installers on both machines, and every time there seems to be a kind of crash in the middle of installation, and then the system reboots into beta 2.

Both systems are installated in their own APFS container (no sharing with 10.15.x). This should be the most basic config. The Mac Mini has about 35 GB of free space, and the BM even over 60 GB. That should be plenty.

Any ideas how to fix that? Anyone else having the same problem? Or an idea how to find the log & error msgs the updater may report?

I could, of course, re-install from scratch, but I'd only use that as a last resort. Still hoping this can be solved.

same problem, hope somebody could help on it.
I will try a new installation with 20A4300b, maybe could fix it.
Try it again and failed again.
Tried to re-install Big Sur beta again and again and restart again, then re-installed beta3 successfully. so, the only way is trying again.
Changelog for beta 3 is explicit that the upgrade will not work in many cases


Installer and Software Update
Known Issues

You might be unable to update macOS Big Sur 11 Beta 3, if Secure Boot is set to No Security. (63434409)

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.

When updating to macOS Big Sur 11 Beta 3, you might be offered an unexpectedly large download rather than an incremental software update. (65753086)
Workaround: Under the “Another update is available” text, click the “More info…” link. This will reveal the incremental update where you can click the Install Now button.

Personally, updating via the alternative 4.xGB upgrade, or the full 12GB installation, in both cases the system reboots back into beta 2.

I'll now look for the "Secure boot is set to no security", and try again, and if it doesn't work out, create the bootable USB media and try yet again.

PS: I've tried to upgrade my Mac mini first, which indeed has a T2, however I don't remember touching any setting on that secure boot utility on the recovery system. Still, it's good to know about those options, as it's important to be sure the setting to allow booting from an external drive is enabled, in case something bad happens to the internal storage.

Or maybe I just wait for beta 4…
I have the same problem on my Mac mini 2018.
Tried the installation 3 times.
The software update shows the full installation (about 12 GB), reboots but doesn't install the beta 3.
Then the software update shows the smaller one (about 5 GB). After loading, while preparing the installation it shows the error "could not load".

Anybody succeeded in some way?
Same problem here with Mac Mini 2018.
Same thing happened here and my solution was:
1) create a bootable usb with the createinstallmedia method specified before
or
2) use option command after trying the regular way and boot from the image that the update 3 procedure left after installing

that should do the trick and don't be surprised the system will boot several times! Be cautious though and do not try this on a production system.
Can't update Big Sur from beta 2 to beta 3
 
 
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