macOS Big Sur Beta 3 - An error occurred preparing the update

I can not update my 2019 iMac 27-inch to macOS Big Sir Beta 3. I always get at An error occurred preparing the update. Failed to personalize the software update. Please try again.

Anyone else experiencing this?

I'm experiencing the same issue on a 16" MacBook Pro.
same issue here! Error occurred MacBook Pro mid-2014
Same for me - 16" MBP
Mee too. Try 3 times then upgrade progress has been done (although taking long time), but my Macbook is still in beta2 version.
same for MacBook Air 13-inch, 2018
Yea same on Macbook Air 13" mid-2013.
here the same with MacBook Pro 13 2020, any hint would be highly appreciated.
Software Update Tool



Finding available software

2020-08-03 08:28:31.504 softwareupdate[3628:137230] Creating client/daemon connection: 8DBD86DD-D6EF-40C5-9E6F-2FCF8162DACC

Downloading macOS Big Sur Beta 3

downloading: 100.00%

Failed to download & prepare update: Error Domain=SUMacControllerError Code=7722 "[SUMacControllerErrorPreflightPrerequisiteCheckFailed=7722] Failed to perform PreflightPrerequisite operation: com.apple.MobileSoftwareUpdate.preflight.error(Preflight):MSUPreflightErrorTargetIsNotSnapshotBooted(6) | The volume can not be used because it is not snapshot booted.
  • > Current device configuration requires an alternate installer to perform the update.: [com.apple.MobileSoftwareUpdate.preflight.error(Preflight):MSUPreflightErrorTargetIsNotSnapshotBooted(6)|Unknown Error Indication|]" UserInfo={SUMacControllerErrorIndicationsSummary=|Unknown Error Indication|, SUMacControllerErrorIndicationsMask=8, SUMacControllerErrorIndicationsDescription=-> Current device configuration requires an alternate installer to perform the update., NSUnderlyingError=0x7fc8dd419ba0 {Error Domain=com.apple.MobileSoftwareUpdate.preflight.error Code=6 "The volume can not be used because it is not snapshot booted." UserInfo={NSLocalizedDescription=The volume can not be used because it is not snapshot booted., NSLocalizedFailureReason=The volume can not be used because it is not snapshot booted., MSUPreflightAlternateInstallerRecommended=true}}, NSDebugDescription=[SUMacControllerErrorPreflightPrerequisiteCheckFailed=7722] Failed to perform PreflightPrerequisite operation: com.apple.MobileSoftwareUpdate.preflight.error(Preflight):MSUPreflightErrorTargetIsNotSnapshotBooted(6) | The volume can not be used because it is not snapshot booted.

  • > Current device configuration requires an alternate installer to perform the update.: [com.apple.MobileSoftwareUpdate.preflight.error(Preflight):MSUPreflightErrorTargetIsNotSnapshotBooted(6)|Unknown Error Indication|], NSLocalizedDescription=Current device configuration and target is invalid for install in the current state. Please try again.}

Same issue here on my Mac Mini. Anyone get around this issue?
I also got this error when I try to update my DTK to macOS Big Sur Beta 4.
yea same with iMac end 2013
Any fix for this? MBP 2018 T2 same issue
Some people are reporting success after reviving BridgeOS on the T2 security chip by using Apple Configurator 2 on a second computer. See https://developer.apple.com/forums/thread/656059
Same problem with MacBook Pro mid-2014
I'm experiencing the same on a MacBook Pro 15" Mid 2014 when trying to upgrade from beta 4 to 5.
macOS Big Sur Beta 3 - An error occurred preparing the update
 
 
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