Unable to create preboot volume for APFS during macOS 10.15 beta installation

After trying all the suggestions in this thread (and all the similiar threads for this problem I was able to google), and before giving up and doing clean installation of newer version, I made a deep dive in the essense of the issue - "coiuld not create Preboot volume..." and FOUND THE SOLUTION THAT PERFECTLY WORKED FOR ME

I found that Preboot volume exists already on my drive (although is umnounted), so most probably running upgrade is just updating it.

I tried to update Preboot manually via

diskutil apfs updatePreboot /Volumes/Macintosh\ HD/

or

diskutil apfs updatePreboot /

And this was unsuccesful due to (luckily this command is pretty well verbosed) absence of one of the AFPS crypto users in Mac users list ("An APFS crypto user was not found in the Open Directory user database"). This led to entire Preboot update was unsuccesful. I carefully checked whether this missing APFS does not exist anywhere in Directory Utility ('Users' in /Local/Default) by comparing GeneratedIUD code.

So, this UUID missed everywhere, although diskutil apfs listcryptousers disk1s1 output was listing such crypto user. Most probably either myself or some program was manipulating users list, and has removed some of them in a non-consistent way, so it has gone from the users list, but was kept as cryptographic user on the filesystem level. And this inconsistency prevented Preboot from being upgraded.

So I removed the cryptouser manually by:

sudo fdesetup remove -uuid {UUID}

Doublechecked via manual Preboot update to see it works well now

diskutil apfs updatePreboot /Volumes/Macintosh\ HD/

And proceeded with upgrade, which was without glitches now!

Happy that I found a solution, but regretfully I wasted as much time, as I would spend on clean straightforward installation and all the backuping/restoring/programs intallations/etc.

Hopefully I can save this time for one of you guys!

Hello.

I had this problem too. Had me scratching my head for a while, but eventually was easily solved.

In my case, for whatever reasons, the system had created 100 preboot mounting points below /Volumes (please excuse formatting):

alfredo@Alfredobot-274 /Volumes> ls
InstallESD    Preboot 18  Preboot 29  Preboot 4   Preboot 50  Preboot 61  Preboot 72  Preboot 83  Preboot 94
Macintosh HD    Preboot 19  Preboot 3   Preboot 40  Preboot 51  Preboot 62  Preboot 73  Preboot 84  Preboot 95
Preboot        Preboot 2   Preboot 30  Preboot 41  Preboot 52  Preboot 63  Preboot 74  Preboot 85  Preboot 96
Preboot 1    Preboot 20  Preboot 31  Preboot 42  Preboot 53  Preboot 64  Preboot 75  Preboot 86 Preboot 97
Preboot 10    Preboot 21  Preboot 32  Preboot 43  Preboot 54  Preboot 65  Preboot 76  Preboot 87 Preboot 98
Preboot 11    Preboot 22  Preboot 33  Preboot 44  Preboot 55  Preboot 66  Preboot 77  Preboot 88 Preboot 99
Preboot 12    Preboot 23  Preboot 34  Preboot 45  Preboot 56  Preboot 67  Preboot 78  Preboot 89
Preboot 13    Preboot 24  Preboot 35  Preboot 46  Preboot 57  Preboot 68  Preboot 79 Preboot 9
Preboot 14    Preboot 25  Preboot 36  Preboot 47  Preboot 58  Preboot 69  Preboot 8   Preboot 90
Preboot 15    Preboot 26  Preboot 37  Preboot 48  Preboot 59  Preboot 7   Preboot 80  Preboot 91
Preboot 16    Preboot 27  Preboot 38  Preboot 49  Preboot 6   Preboot 70  Preboot 81  Preboot 92
Preboot 17    Preboot 28  Preboot 39  Preboot 5  Preboot 60  Preboot 71  Preboot 82  Preboot 93

The fix was as simple as to rm -r those /Volumes/Preboot*. I did leave /Volumes/Preboot and /Volumes/Preboot 99 just in case. After Catalina was installed, they were gone.

That's all. Hope it helps someone.

So this is crazy but I had 2 USB devices plugged in (headphones and a selfie-lamp). Unplugging these devices got me up and running again. All I can think is one of the USB devices had a mini storage device inside it and my Mac was trying to install OSX on it.

For others that might encounter, probably something like this to create a missing preboot: 

Enter recovery and open terminal.

diskutil list (to get disk for virtual apfs container to use below)

diskutil  apfs addVolume disk2 apfs Preboot -role B

diskutil info disk2s1 | grep "Volume UUID"

mkdir /Volumes/Preboot/A579A99E-9795-4086-890E-04E2112D1E78 (UUID from previous command)

diskutil apfs updatepreboot /Volumes/Macintosh HD

Reboot back in to recovery so FileVault syncs up with volume. Reinstall operating system over existing. This is nondestructive.

There might be a shortcut to reinstalling the OS, but this is as deep as I went.

I encountered the same issue upgrading from 10.15.2 to 12.5. "diskutil list" showed my volumes were already APFS.

Solution for me was to do:

diskutil apfs updatePreboot /Volumes/Macintosh\ HD/

and then reboot (not sure if that was necessary) and then Preferences -> Software Update -> install Monterey.

Thanks to the contributors to this thread which helped point me in the right direction!