How to Fix Windows Upgrade Error 0xc1900101

Windows upgrade error 0xc1900101 usually means Setup hit an incompatible, damaged, or incorrectly installed device driver and rolled Windows back to the previous installation. Fix it by backing up your files, disconnecting nonessential USB devices, updating drivers and firmware, freeing storage space, removing software that installs low-level drivers, and using setup logs to identify the fault if the upgrade fails again.

What does Windows upgrade error 0xc1900101 mean?

0xC1900101

This error family most often points to an incompatible, damaged, or incorrectly installed device driver. The failure may involve storage, graphics, chipset, network, audio, Bluetooth, or another device that Windows Setup needs during the upgrade. Firmware, third-party security software, and system utilities can produce similar symptoms.

The code does not identify the device by itself. You may also see a suffix such as 0xC1900101–0x30018 or 0xC1900101–0x20017. The suffix indicates the setup phase and timing of the rollback, but the setup logs are usually needed to name the driver.

The rollback normally occurs after Windows has copied files and restarted the computer. Setup then loads the new Windows environment, checks drivers and hardware, and encounters the conflict. The computer may restart several times before returning to the previous Windows version. If Windows has already rolled back successfully, your personal files should remain in place, but check important data before trying again. Applications or settings are not guaranteed to be unaffected.

Is your PC ready for these fixes?

These steps apply primarily to Windows 10 and Windows 11 feature upgrades performed through Windows Update, the Windows Installation Assistant, or Windows installation media. You need an account with Administrator privileges for driver changes, system-file repairs, clean-boot changes, and SetupDiag. Some steps require a restart.

Back up documents, photos, browser data, and any other files you cannot replace. Use an external backup drive or a trusted cloud location, and confirm that the backup opens. Do not begin deeper repair work until the backup is complete.

Record the exact error, including its suffix, from Windows Update, the rollback screen, or the setup logs. Also record your current Windows version.

Settings > System > About > Windows specifications

Check free space on the system drive. Feature upgrades need working space for downloaded files, temporary files, and the previous Windows installation. If the drive is nearly full, remove temporary files or move large personal files after confirming they are backed up.

Disconnect nonessential hardware before retrying the upgrade. Remove USB docks, printers, scanners, external drives, card readers, webcams, game controllers, and similar devices. Leave the keyboard, mouse, display, network connection, and installation media connected as needed. A desktop computer should have only the hardware required to start Windows.

Do not disconnect a drive that contains the only copy of your files. If BitLocker is enabled, make sure you can access your recovery key before changing firmware or boot settings.

Fix 0xc1900101 in the safest order

Follow these steps in order. Restart after driver, firmware, or system-file changes when Windows requests it.

1. Install current Windows updates, device drivers, and firmware. Open Windows Update and install all available updates. Then visit the computer or motherboard manufacturer's support page and update the chipset, storage controller, graphics, network, and audio drivers that match your exact model and Windows version. If the manufacturer provides a BIOS or UEFI update, follow its instructions carefully and keep the computer connected to reliable power.

Settings > Windows Update > Check for updates

You need Administrator permission for driver and firmware changes. Prefer drivers supplied by the computer or component manufacturer over generic driver-download sites. In Device Manager, look for devices with a warning icon. Right-click a suspect device, choose Properties, and inspect the General and Driver tabs. If a driver was recently changed and the problem began afterward, use Roll Back Driver when that option is available.

The upgrade should have current manufacturer drivers and firmware, with no unresolved devices in Device Manager. If the problem remains, continue; do not install random driver packages repeatedly.

2. Free space on the system drive. Remove temporary files or move large personal files only after confirming that the files are backed up. Do not delete files from an external drive or disconnect a drive that contains the only copy of your data.

Feature upgrades use space for downloaded files, temporary files, and the previous Windows installation. If the drive is nearly full, retry the upgrade after making room. If it still rolls back, continue to the next step.

3. Remove hardware and software that can interfere with Setup. Keep nonessential USB devices disconnected. Temporarily uninstall third-party antivirus, endpoint protection, disk-encryption tools, hardware monitoring software, overclocking tools, virtual drive software, and manufacturer utilities that install low-level drivers. Use the software vendor's removal tool when its normal uninstaller leaves a filter driver behind.

Settings > Apps > Installed apps

You need Administrator permission. Windows Security can provide protection while third-party antivirus is removed, but follow your organization's security policy on a managed PC. Restart after removal and retry the upgrade. If it still rolls back, the cause may be a device driver rather than the security software.

4. Run the Windows Update troubleshooter. It can repair update-service configuration and clear some common update problems, though it cannot correct every driver conflict.

Settings > System > Troubleshoot > Other troubleshooters > Windows Update > Run

Apply the recommended repair, restart, and try Windows Update again. If the troubleshooter reports that it could not identify a problem, continue with system-file repair.

5. Repair the Windows component store and protected system files. Open Windows Terminal or Command Prompt as Administrator and run these commands one at a time. Wait for each command to finish.

DISM.exe /Online /Cleanup-Image /RestoreHealth
sfc.exe /scannow

DISM repairs the component store that Windows uses for servicing. sfc checks protected system files and replaces damaged copies. A successful sfc result says that Windows Resource Protection did not find any integrity violations, or that it found and repaired corrupted files. Restart after the repairs, then retry the upgrade.

If DISM reports that source files could not be found, do not guess at a source path. The repair may need matching Windows installation media or an administrator to provide a valid repair source. If sfc says it could not repair some files, inspect the CBS log and continue to the setup-log investigation rather than repeating the upgrade indefinitely.

6. Perform a clean boot and retry the upgrade. A clean boot starts Windows with Microsoft services and essential drivers while preventing many third-party services from loading.

Win + R > msconfig > Services > Hide all Microsoft services > Disable all

Open Task Manager from the Startup tab, disable enabled third-party startup items, apply the changes, and restart. You need Administrator permission. Run the upgrade with nonessential hardware still disconnected.

If the upgrade completes in the clean-boot environment, re-enable services and startup items in groups, restarting between groups, until the conflicting software is identified. Restore normal startup afterward. If it still fails, inspect the rollback logs before making more changes.

How to find the driver that caused the rollback

When the basic fixes do not work, use the logs to identify the failed setup phase and, sometimes, the exact .sys driver. The logs may be removed or replaced by a later attempt, so copy them before retrying the upgrade.

The most useful locations are:

C:\$WINDOWS.~BT\Sources\Panther\setupact.log
C:\$WINDOWS.~BT\Sources\Panther\setuperr.log
C:\$WINDOWS.~BT\Sources\Rollback\setupact.log
C:\$WINDOWS.~BT\Sources\Rollback\setuperr.log

The $WINDOWS.~BT folder may be hidden, and access can require Administrator permission. Open the files in Notepad and search for the recorded suffix, rollback, error, failed, driver, .sys, and 0xC1900101. The Rollback folder is especially useful after Windows has returned to the previous version. A failure during SAFE_OS, for example, points to the part of Setup running after the restart, when drivers and firmware are being initialized.

The log may identify a driver as oem42.inf rather than by a friendly device name. Map third-party driver packages with an elevated Command Prompt:

pnputil /enum-drivers

Match the published name, provider, class, and original file information in the output. Do not remove a driver solely because it appears in the list. Confirm that it belongs to the failing device, then update or uninstall that device's software through Device Manager or the manufacturer's supported removal process.

You can also use Microsoft's SetupDiag utility. Download it from Microsoft, place it in a folder you can find, and run it as Administrator after the rollback. SetupDiag reads Windows Setup logs and creates a results file, commonly named SetupDiagResults.log, in the folder where it runs or in the location shown by the utility.

SetupDiag.exe

Read the result for the matching rule, failure phase, error code, and driver or package name. If SetupDiag reports a specific driver, BIOS version, storage controller, or filter software, repair that item before attempting the upgrade again. If it reports only a general rollback, preserve the logs and search for the first meaningful failure before the final rollback entry; the last error is often a consequence rather than the cause.

How to confirm the upgrade worked and prevent another failure

After Windows finishes the upgrade, let the computer restart normally. Verify the installed version instead of relying only on the absence of an error.

Settings > System > About > Windows specifications

Confirm that the edition and version match the upgrade you intended to install. You can also press Win + R, enter winver, and check the displayed Windows version. Run Windows Update once more and open Device Manager.

Windows should report the new version, Windows Update should show no pending failed upgrade, and Device Manager should have no warning icons. If a device is missing or malfunctioning, install its current manufacturer driver before reconnecting other peripherals.

Reconnect disconnected hardware one item at a time. Restart or test Windows after each important device is restored. This identifies a dock, printer, storage device, or adapter that triggers a new problem.

If the same 0xC1900101 error returns after rollback, do not repeat the upgrade unchanged. Record the new suffix, save the new Panther and Rollback logs, and compare the failing phase with the earlier attempt. Resolve the named driver, update or roll back the related BIOS or firmware, or remove the software that installed the filter driver. If the logs point to storage or motherboard firmware, obtain the exact update for the computer model and follow the manufacturer's recovery instructions. Keep your backup and BitLocker recovery key available before firmware work.

Conclusion

Back up your files, disconnect nonessential hardware, and work through the fixes in order. If the upgrade rolls back again, preserve the new logs and run SetupDiag before changing more drivers; use the identified driver or firmware conflict to choose the next repair.

Frequently Asked Questions

Will fixing 0xc1900101 delete my personal files?

These troubleshooting steps target drivers, services, firmware, and Windows system components; they are not intended to delete personal files. Back up important data first. Do not choose a reset, format, or clean installation unless you understand the consequences.

Should I uninstall every driver before upgrading?

No. Remove or roll back only drivers identified as suspect by Device Manager, the setup logs, SetupDiag, or a recent hardware change. Removing essential storage, chipset, or display drivers without a replacement can make Windows unstable.