Hi Ludwig,

This 80240020 error means that your Windows 10 installation folder is unfinished and/or corrupted.

You can follow the below methods to resolve this error:

Method 1: Delete downloaded files and try again

The first thing is to delete all downloaded files and try again. It seems sometimes the Windows 10 setup files are corrupt. You can delete them and force downloading them again on the command line. Here is what you need to do:

• Open your Windows Explorer
• Go to C:\Windows\SoftwareDistribution\Download
• Delete all files in this folder. Don’t be afraid, these are just temporary files that you can delete safely. Windows will download them again if necessary.

Note: you might have to kill the process WindowsUpdateBox.exe in your task manager if the files are still in use and cannot be deleted.

After this you have to force starting the update process on the command line:
Launch your command line as administrator. In order to do this open your start menu (Windows 7) or your start screen (Windows 8) and type cmd.

Right-click the Command prompt item and select Run as administrator.
Enter wuauclt.exe /updatenow.

Now go to your control panel and select Windows Update you should be able to to see that Windows 10 is being downloaded.

Method 2: Set secret registry key to enable Windows 10 upgrade
Follow the below steps:

• Press Win+R to open the Run dialog. Type regedit and press Enter to start the Registry Editor.
• Go to HKEY_LOCAL_MACHINE\ Software\Microsoft\Windows\CurrentVersion\WindowsUpdate\ OSUpgrade
• (If the key does not exist create it)
• Right-click the blank area in the right pane and select New/DWORD Value.
• Enter AllowOSUpgrade and press Enter.
• Double click the new item and set its value to 1.
• Open your control panel and check for updates.

Windows 10 upgrade should start immediately. You might have to restart your computer if the update does not start right away.

Method 3: Use the Windows download tool
Just download the media creation tool provided by Microsoft and follow the instructions.
http://www.microsoft...

The tool will create a bootable USB drive or DVD from which you can install Windows.

I hope this helps in getting Windows 10 installed in your machine without any errors.

Regards,
Lokesh