Windows 10: Upgrade error 0xC1900101-0x2000A

[German]Some users are receiving error 0x8007002C-0x4000D during upgrading a Windows 7/Windows 8.1 machine to Windows 10. Here are a few hints. 


Users are observing this error under Windows 7 as well as under Windows 8.1 and also during upgrades from Windows 10 Insider Preview builds. Upgrade stops at 25% and the error message appears:

The installation failed in the SAFE_OS phase with an error during PREPARE_FIRST_BOOT operation

I've observed this error code during upgrading to Windows 8.1 (see my German blog post Windows 10: Upgrade-Fehler 0xC1900101-0x2000A).

Try a log file analysis

To find out, what causes this error code, try to analyze the log files created during setup. All log files are collected in hidden folders:


Folder Panther contains *.log files, whilst folder Rollback contains *.txt files. Just copy these  *.log files via explorer to desktop and open it in Windows editor notepad. Then search for the error code. In some cases, some additional hints may be found.

Other troubleshooting actions that may help

If a log file analysis doesn't provide any clue about the root cause, you can process the following checks to prevent show stoppers:


  • Uninstall your firewall, antivirus und security software. I've done a web research and found several cases, where security software blocked the upgrade.
  • Remove all unused SATA devices. I found incidents (here, here), that DVD drives and additional SATA disks has been the root cause for install trouble. Background-info: Some mainboards are using SATA controllers which doesn't support AHCI mode required from setup.
  • Also take care, that your hard disks are not formatted as dynamic disks. I've seen several incidents, that this was the show stopper.
  • Also cloned SSD's (from hard disks) has been identified as show stoppers.
  • Some users are forced to remove wrong WWAN miniport entries in device manager or deactivate the WLAN adapter.
  • Remove all devices not necessary to upgrade, de-install unused drivers and deactivate the devices in device manager. Also update all remaining drivers.

Also overclocked systems or damaged Windows files has been the cause for this issue. Try to fix Windows corruption errors by using the DISM or System Update Readiness tool, as recommended in KB947821.

Have also a look into this US MS Answers-Wiki (German edition Windows 10: Installations- und Upgrade-Troubleshooting).

Further reading:
Win10 Wiki
Cumulative Windows 10 Update KB3081424 fails to install (Fix)
Is EaseUS Partition Master 10.5 a Windows10 upgrade killer?
Windows 10: Dropping App Store Error 0x803F7003

Windows 10: Upgrade error 80240020
Windows 10: Upgrade error 0x80200013
Windows 10: Upgrade error 0xC1900101 – 0x20004

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