Dear Radandeep,
Yes I have tried and re-tried ALL the proposed solutions up to last Thusrday (15 May).
None of them worked.
I have also tried to restore my computer to previous point, and re-update. Updates failed again and again... (always the three indicated above, other were correctly installed apparently).
I hope that I will not have to make a refresh as I will have to reinstall all the other sofware and customizations as I understood from the "info windows". (Worst, a full re-installation!).
Actually, I cannot afford to do it currently due to other work emergencies.
I have been informed that I am not the single one facing such problems.
So I hope you will find a solution to this problem quickly.
Thanks and regards
MB