This issue affects devices that have one of the following histories:

• The device previously received a Windows 10 feature update that used a custom SetupConfig.ini file.
• Earlier updates or upgrades to the device used language packs or post-upgrade scripts that were manually configured or deployed.

The upgrade failed because of a legacy SetupConfig.ini file that contains hard-coded paths to outdated language packs and scripts. Those language packs and scripts aren't compatible with Windows 11. The path to the legacy file typically is C:\Users\Default\AppData\Local\Microsoft\Windows\WSUS\SetupConfig.ini. The contents of the file resemble the following excerpt:

[SetupConfig]
InstallLangPacks=C:\ProgramData\Temp\Inplaceupgrade\W10_22H2\LP
PostOOBE=C:\ProgramData\Temp\Inplaceupgrade\W10_22H2\Scripts\SetupComplete.cmd
PostRollback=C:\ProgramData\Temp\Inplaceupgrade\W10_22H2\Scripts\ErrorHandler.cmd
DynamicUpdate=Disable

These outdated references cause identity mismatches during the upgrade process. Therefore, the upgrade fails and rolls back.

The original article includes a standard notice here: "Important registry alert".

To remove the legacy information, follow these steps:

1. On the affected computer, open File Explorer, and then go to C:\Users\Default\AppData\Local\Microsoft\Windows\WSUS\.

   Note

   If you can't see the AppData folder, select View > Show, then select Hidden items to view hidden files and folders.

2. Delete the SetupConfig.ini file.

3. Open Registry Editor, and then go to the HKEY_LOCAL_MACHINE\SYSTEM\Setup subkey.

4. Delete the UnattendFile registry entry.