CIS 3.13.119746.572 won't update its virus definitions ?

Please guys,
I I’ve just installed the latest CIS and when I tried to manually update virus definitions, it doesn’t seem to work. I can see the download box but no indication it’s actually downloading anything. Is that true that the virus definition file is around 100 Mo?? that could explained why it take so much time to download?
thank you,
Luc :-\ (CNY)