How to force Download Windows 10 updates?

Windows 10 is released. At least some users report errors during the initial download or during installation of the new operating system.
Windows 10 is finally available and while many users have seen their machines get upgraded automatically to the new operating system, some have reported errors and issues that prevented the upgrade from completing successfully.
This ranged from update servers that were unavailable to specific error codes such as C1900200, 80240020 or the unhelpful “something happened” error.
Here’s how to download Windows 10 updates by forcing Windows to download windows 10 updates and fixing various error and issues.
Solutions have already been found for some issues. For error 80240020 for instance, you need to perform the following operation to start a force download of Windows 10 update on Windows 8 or Windows 8.1 PCs and Laptops:

1. Delete all files in the folder C:\Windows\SoftwareDistribution\Downloads
2. Run the command wuauclt.exe /updatenow on an elevated command prompt (Tap on the Windows-key, type cmd, right-click on the command prompt result and select run as administrator).
3. Check Windows Update again and the download should start anew.