Where are Windows 11 first-boot OOBE errors logged when Event Viewer shows nothing

Diagnosing a failed Windows 11 deployment relies on a set of documented setup and servicing logs. The Panther folder contains setupact.log and setupdev.log with phase-level success and failure codes. Event Viewer Windows Logs System and Application includes entries from Microsoft-Windows-Setup, DISM and Client-Side Extension. Component servicing outcomes are captured in %WINDIR%\Logs\CBS\CBS.log.

The logging coverage during first-boot OOBE is unclear. Findings indicate that certain transient errors in the OOBE phase are recorded only in the hidden file %WINDIR%\Panther\UnattendGC\setupact.log and are not surfaced in the standard Event Viewer. Log locations can differ with non-system drive installs or Panther redirection via unattend.xml, and error code meanings can change between Windows 11 releases.

Does Microsoft document that OOBE-phase transient errors are intentionally omitted from Event Viewer? Which Windows 11 builds consistently write OOBE errors to Panther\UnattendGC\setupact.log versus the main Panther log? When should administrators inspect UnattendGC logs in addition to standard Event Viewer and CBS logs?