Ivo, The above is the *most* likely cause of the updating issue. 0×80240020 WU_E_NO_INTERACTIVE_USER Operation did not complete because there is no logged-on interactive user.

0×80240016 WU_E_INSTALL_NOT_ALLOWED Operation tried to install while another installation was in progress or the system was pending a mandatory restart. Does the issue occur when searching for, downloading, or, installing updates ? Error message when you try to install updates from the Windows Update