If automatic updates (signatures and product) are disabled, the manual "update" function is greyed out -- manual updates are not possible unless automatic updates are enabled.
It is inappropriate for me to have any automatic updates enabled on my system, so the first thing I do when I install a product with such features is to disable them. I perform manual updates, exclusively and frequently.
I have been using manual updates exclusively with ZAES for many years. I just upgraded to v10, renewed my annual subscription, then discovered that it is no longer possible to perform only manual updates. Tech support just confirmed that this change in behavior introduced with v10 is by design.