Solution for error code 80240020 when upgrading Win10

Win7/Win8.1 users who have subscribed to the Win10 upgrade may encounter an 80240020 error message during Windows Update when upgrading the system. This error usually occurs when the system installation file has been downloaded and is ready for installation.

According to Microsoft's Q&A community's answer, the reason for this error is:

Under normal circumstances, users need to first confirm the interaction through Windows Update through Windows Update. It is the largest software upgrade ever, hoping to provide a better user experience for users. Microsoft has not yet prepared for all devices. It is recommended that users who have not received the upgrade notification wait for a while until the system starts to upgrade.

This issue may occur because many users have previously forced the system to start an upgrade by command without confirming with an upgrade reminder. For users who encounter the 80240020 error message, if you want to upgrade immediately, you can try to modify the registry by:

• Open the run by Win+R, enter regedit to open the registry editor;

• Navigate to

HKEY_LOCAL_MACHINE\\SOFTWARE\\Microsoft\\Windows\\CurrentVersion\\WindowsUpdate\\OSUpgrade

• Create a new DWORD named AllowOSUpgrade on the right side (32-bit Value, double-click the new value to set its value to 1, as shown below:

After the modification is complete, open the system Windows Update to check the update, you should be able to click "Start Update" Button to upgrade Windows10. Note: Windows 8.1 users need to open Windows update in the traditional control panel instead of Windows Update in the Modern version.