0xc1900101
Moderate
Microsoft · Windows
Installation rollback during a Windows upgrade. The upgrade process encountered a driver compatibility error during the SAFE_OS phase and rolled back to the previous version.
Quick Answer
Error code 0xC1900101 on your Microsoft Windows means: Installation rollback during a Windows upgrade. The upgrade process encountered a driver compatibility error during the SAFE_OS phase and rolled back to the previous version.. This is usually fixable — see the step-by-step guide below.
Affected Models
Applies to all models
Likely Causes
How to Fix It
1
Update all device drivers before retrying the upgrade: Visit your PC manufacturer's support page and download the latest drivers for graphics, chipset, storage, and network controllers.
2
Uninstall third-party antivirus software completely (not just disable) before the upgrade. Use the vendor's official removal tool for thorough uninstallation.
3
Disconnect all unnecessary peripherals: Remove USB devices, external drives, docking stations, printers, and secondary monitors before starting the upgrade.
4
Ensure at least 30 GB of free space on the system drive. Run Disk Cleanup with 'Clean up system files' to free space.
5
Update your BIOS/UEFI firmware: Check your PC manufacturer's support page for the latest firmware version and apply it before retrying.
6
Check the setup error log for specific sub-error codes: Review C:\$WINDOWS.~BT\Sources\Panther\setuperr.log. Common sub-codes like 0xC1900101 - 0x20017 point to driver issues during SAFE_OS with INSTALL_RECOVERY_ENVIRONMENT operation.
7
Run the Windows Setup compatibility check without upgrading: From the mounted ISO or Media Creation Tool, run setup.exe and stop at the compatibility report to identify blocking issues.
8
Disable Secure Boot and BitLocker temporarily in BIOS before retrying the upgrade.
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
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