Your preview window doesn't update when you hit the prescan button? This is most likely a problem which is connected to macOS 13 Ventura and SilverFast 8. SilverFast 8 uses a version of Apple's color management system which was up to date when SilverFast 8 was created and which could be used until the latest update of macOS. Apple no longer supports this color management system with macOS 13.
You can disable the color management completely in the preferences' CMS tab, but that really isn't a good solution to this. The color profile and management is very important for the accuracy of your scans.
We therefore recommend to upgrade to SilverFast 9 which uses a modern little CMS color management system which works without these issues.
As a user of SilverFast 8, you can enter your serial number in our online shop to purchase SilverFast 9 as upgrade at a reduced price.