Unable to install BigSur Beta 3

facing the same issue...u can go to folder

/var/log/install.log

and get the reason.

Thanks for the pointer. I tried one more time with a new volume and get this in the log:

2020-07-31 08:37:41-07 Mac-Pro osinstallersetupd[1096]: Retrieved package com.apple.dmg.BaseSystem (linkfile-validated:///Volumes/EtaBeta/macOS%20Install%20Data/UpdateBundle/AssetData/Restore/BaseSystem.chunklist:::/Volumes/EtaBeta/macOS%20Install%20Data/UpdateBundle/AssetData/Restore/BaseSystem.dmg)

2020-07-31 08:37:41-07 Mac-Pro osinstallersetupd[1096]: Starting bridgeOS update prepare

2020-07-31 08:38:14-07 Mac-Pro osinstallersetupd[1096]: bridgeOS prepare summary: 17P6065 -> 18P50335d, update = 18.16.10335.5.4, brain = 18.16.10335.5.4, variant = com.apple.bridgeOSCustomer, macOS = 19G73 (customer), project = BridgeOSInstall-77, userAuth = 0, prod fused = 1, model = j160ap, client = InstallAssistant, retries = 2, session = 9EFAC8A8-1385-4DC5-A188-0903C60C6B85: Error Domain=BOSErrorDomain Code=204 "An error occurred during preflight." UserInfo={NSLocalizedDescription=An error occurred during preflight., UpdateBundleIdentifier=com.apple.bridgeOSCustomer, NSUnderlyingError=0x7f8a86423a70 {Error Domain=BridgeOSSoftwareUpdateError Code=19 "MSU - 37 (FCRT migration failed.);NSPOSIXErrorDomain - 2 (failed to statfs /private/var/hardware);" UserInfo={SystemPartitionSize=1979666432, MSUErrorCode=37, MSUErrorDescription=FCRT migration failed., NSLocalizedDescription=MSU - 37 (FCRT migration failed.);NSPOSIXErrorDomain - 2 (failed to statfs /private/var/hardware);}}}

2020-07-31 08:38:14-07 Mac-Pro osinstallersetupd[1096]: bridgeOS update prepare complete

2020-07-31 08:38:14-07 Mac-Pro osinstallersetupd[1096]: bridgeOS update prepare failed: Error Domain=BOSErrorDomain Code=204 "An error occurred during preflight." UserInfo={NSLocalizedDescription=An error occurred during preflight., UpdateBundleIdentifier=com.apple.bridgeOSCustomer, NSUnderlyingError=0x7f8a86423a70 {Error Domain=BridgeOSSoftwareUpdateError Code=19 "MSU - 37 (FCRT migration failed.);NSPOSIXErrorDomain - 2 (failed to statfs /private/var/hardware);" UserInfo={SystemPartitionSize=1979666432, MSUErrorCode=37, MSUErrorDescription=FCRT migration failed., NSLocalizedDescription=MSU - 37 (FCRT migration failed.);NSPOSIXErrorDomain - 2 (failed to statfs /private/var/hardware);}}}

2020-07-31 08:38:14-07 Mac-Pro osinstallersetupd[1096]: Operation queue failed with error: Error Domain=com.apple.OSInstallerSetup.error Code=602 "An error occurred installing macOS." UserInfo={NSLocalizedRecoverySuggestion=You can try again to complete the installation., NSLocalizedDescription=An error occurred installing macOS., NSUnderlyingError=0x7f8a86423aa0 {Error Domain=BOSErrorDomain Code=204 "An error occurred during preflight." UserInfo={NSLocalizedDescription=An error occurred during preflight., UpdateBundleIdentifier=com.apple.bridgeOSCustomer, NSUnderlyingError=0x7f8a86423a70 {Error Domain=BridgeOSSoftwareUpdateError Code=19 "MSU - 37 (FCRT migration failed.);NSPOSIXErrorDomain - 2 (failed to statfs /private/var/hardware);" UserInfo={SystemPartitionSize=1979666432, MSUErrorCode=37, MSUErrorDescription=FCRT migration failed., NSLocalizedDescription=MSU - 37 (FCRT migration failed.);NSPOSIXErrorDomain - 2 (failed to statfs /private/var/hardware);}}}}}

2020-07-31 08:38:14-07 Mac-Pro InstallAssistant[1095]: Stopped operation queue with Error Domain=com.apple.OSInstallerSetup.error Code=602 "An error occurred installing macOS." UserInfo={NSUnderlyingError=0x7fe4a750ec50 {Error Domain=BOSErrorDomain Code=204 "An error occurred during preflight." UserInfo={NSUnderlyingError=0x7fe4a7587f80 {Error Domain=BridgeOSSoftwareUpdateError Code=19 "MSU - 37 (FCRT migration failed.);NSPOSIXErrorDomain - 2 (failed to statfs /private/var/hardware);" UserInfo={SystemPartitionSize=1979666432, MSUErrorCode=37, MSUErrorDescription=FCRT migration failed., NSLocalizedDescription=MSU - 37 (FCRT migration failed.);NSPOSIXErrorDomain - 2 (failed to statfs /private/var/hardware);}}, NSLocalizedDescription=An error occurred during preflight., UpdateBundleIdentifier=com.apple.bridgeOSCustomer}}, NSLocalizedRecoverySuggestion=You can try again to complete the installation., NSLocalizedDescription=An error occurred installing macOS.}

Same error here beta 3 & 4 MBP 2019

Also the same error message.

This is also not working with creationmedia as startvolume and in recovery mode, always the same error.

Just tried Beta 4 and got the same error and same log error. Went into recovery more and lower security to none but no change. Still error out.

Having the exact same issue here. Changing all security settings made no difference.

Having the same issue on installing Beta 4. Creating new admin user did not resolve the problem.

Same error here. I've tried booting to installation media and simply running from within macOS, same error every time.

exactly the same error here with Beta 3 and 4

Here the same issue by Beta 4. Even with a fresh installation of Catalina i get this error

Same error here. 19 MBP. After some digging it seems to be related to bridgeOS (T2 chip) version. Not sure if it's a bug... That's why reviving device using Apple Configurator 2 may work (see this post)

Same error with the public beta

APPLE seriously needs to address this issue !!! facing the same problem since developer beta n now same error with the PUBLIC BETA too...WTH..?!!!

OK I managed to solve the problem by reviving the device following this guide: https://support.apple.com/en-gb/guide/apple-configurator-2/apdebea5be51/mac

Same error here with mac mini 2018. I've reported to Apple by feedback but got no answer yet. The following steps tried but no use:

• Restart ❌

• Redownload & reinstall ❌

• Erase the disk and reinstall ❌

• Install previous version ❌

• Create another admin account and install ❌

• Create new APFS volume and install ❌

• Install in recovery model ❌

• Reset SMC ❌

Such terrible experience...

Solved with the "Reviving the T2 chip" suggestion. https://support.apple.com/en-gb/guide/apple-configurator-2/apdebea5be51/mac

I hope Apple will look into this since the current workaround is a bit convoluted (you need another Mac) and definitely not obvious.

Luckily the revive didn't mess with the drive so no data loss.

Thank you albertaki !

Guido