LaserSoft Imaging

I'm using Silverfast 6.5.5r5 to calibrate with iT8 a Hp scanner for a professional application.
It was working fine till today. Then suddenly when I run a prescan or else a scan the image I see on the screen is fully black.
What happened? How to solve?
When I use windows tool to take a scan it works normally and I have the picture.

Dear customer,

please update to the latest free update for your SilverFast product (6.6.2r5).
Your version is very outdated.

Kind regards,
Arne Ketelhohn.

Thanks for the suggestion and for the fast reaction.
In the meantime I cleaned the Pref and it restarted working normally.
Bye