Why "preparing for install Windows 10 Home, 1511, 10586," stops at 32%?

[lffs]

My HP Pavilion dv6 was upgraded to Windows 10 Home in August 2015 by downloading the new OS over Windows Update (Update & Security/Settings). That was a very smooth procedure. However, since November 2015, Windows Update automatically downloads the Windows 10 Home, version, 1511, 10586. The download completes with no problem. But once it starts the "preparing for install", this process goes smooth up to 23%. After almost one hour at 23%, the screen goes black. By activating the touchpad, the screen lights again, when the preparing for install counting jumps to 32%, gets stuck and stops suddenly. A message comes to the Windows Update screen, indicating that an error had occurred and suggesting "please try again" or seek support on the web. This has been extremely annoying. Any suggestion on what to do to fix this problem? Thanks for your help!