Log files and resolving upgrade errors - Windows Deployment ...
docs.microsoft.com › en-us › windowsAug 30, 2021 · These log files are essential for troubleshooting upgrade problems. By default, the folders that contain these log files are hidden on the upgrade target computer. To view the log files, configure Windows Explorer to view hidden items, or use a tool to automatically gather these logs. The most useful log is setupact.log. The log files are located in a different folder depending on the Windows Setup phase.