Error C1900101-4000D comes up when trying to install Windows 10. This i must say; is a dreaded error and several fixes available online do not work for the majority of people having this issue. There are quiet a few work arounds such as “Doing a clean install of Windows 10” but that will invalidate the free activation / upgrade offered. In short, you get the free windows 10 when you upgrade, and if you do a reinstall after the upgrade, Windows 10 will continue to stay free. Sort of a hassle when it’s free, then it should be free either way but this is not the case.
Before you begin; please disable your Firewall/Antivirus Software if it is not the default Microsoft’s Firewall/Defender since they are also known to interrupt the upgrade process by blocking the processes needed to initiate the upgrade.
Delete Registry for Mounted Images
Hold Windows Key and Press R. In the run dialog that opens up type regedit and click OK. In the registry editor; navigate to the following path and delete the strings data. Exit Registry Editor and re-try upgrade to Windows 10.
Disable Your Wi-Fi Adapter & CD/DVD Drive
Hold the Windows Key and Press R. Type hdwwiz.cpl and Click OK. expand Network Adapters and right-click your wifi adapter; then choose Disable, do the same for CD/DVD Drive from the Device Manager. If it works and Windows 10 installs; then uninstall the wi-fi driver and re-install the latest one from the manufacturer’s website and just enable the DVD/CD.
Uninstall Cyberlink Programs from Control Panel
Hold the Windows Key and Press R. Type appwiz.cpl and Click OK. Locate Cyberlink Products and uninstall them one by one. After they have all been uninstalled; reboot PC and test upgrade.
In addition to the steps listed below; there are a few similar steps here which may help for upgrade from Windows 8/8.1 by disabling the driver signatures.