Windows Update Windows Update Needs an admin

0xC1900101: Windows upgrade failed, usually because of a driver

Likely causes

• An outdated or incompatible third-party driver.
• External hardware plugged in during the upgrade (docks, drives, extra devices).
• Not enough free disk space.
• Third-party security software interfering.
• Disk errors or damaged system files.

How to fix it

1. Free up space: at least 20 GB for 64-bit Windows (16 GB for 32-bit).
2. Install all available updates and drivers from Windows Update, then get newer drivers from the hardware maker for anything else.
3. Unplug everything not needed: docks, external drives and extra devices. Open Device Manager and fix any device with a yellow warning.
4. Uninstall third-party antivirus for the upgrade (Microsoft Defender protects the PC meanwhile), and reinstall it afterwards. Have its install files and license ready first.
5. As administrator, run chkdsk /f C: (it runs at the next restart) and DISM.exe /Online /Cleanup-image /Restorehealth, then try the upgrade again.

Checked against: support.microsoft.com