While waiting for Windows 10, some users may see Windows Update Installation Failure 80240020 logged under Windows Update History.
This is an expected message indicating that when installation begins it may require user interaction. This is the largest software upgrade event ever and they’re managing it so everyone has a great experience. They recommend waiting until your PC receives a notification to upgrade, and then following the instructions provided.
Please note that there is no problem with your reservation or upgrade download. The upgrade download is not corrupt as some have stated, and you will be notified in the coming days or weeks when your device is ready to upgrade.
If you are very eager to upgrade, tech savvy users with the above message can modify the following registry key to install immediately.
Warning: Serious problems might occur if you modify the registry incorrectly. Before you modify it, back up the registry for restoration in case problems occur.
- Locate the registry key: [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\OSUpgrade]
- It should exist, but if not, create it.
- Create a new DWORD (32-bit) Value with Name = “AllowOSUpgrade” (without the quotes), and set the Value = 0x00000001.
Once the registry key is modified, close and reopen the desktop Control Panel, go to Windows Update and check for updates. You should now be able to click the Get Started button to upgrade to Windows 10. Note: Windows 8.1 users must go to the desktop Control Panel, and not the modern Windows Update UI.”