Windows 11 Insider Build 26220.9223 fails with 0xC1900101

Error 0xC1900101 followed by rollback usually indicates a driver or low-level hardware compatibility failure, not a stopped Windows Update service. Disconnect USB devices and third-party storage, ensure sufficient free space, and install UEFI, chipset, storage, graphics, and network drivers from the PC manufacturer. Remove or temporarily uninstall third-party antivirus, disk-encryption filters, virtual-drive tools, and obsolete VPN drivers, then try from a clean boot. After rollback, inspect setupact.log and setuperr.log under the Windows setup Panther and Rollback folders, or run Microsoft SetupDiag, to identify the last driver or phase before failure. Do not reset Windows Update components; the download completes and the failure occurs during setup. Check the known issues for build 26220.9223 and confirm the device meets that Insider channel’s requirements. If the logs identify no removable driver, submit them with the error, current build, channel, and Feedback Hub link to the Windows Insider team rather than forcing the upgrade.