Using the Manager, you may need to adjust scanner settings in the Scanner settings dialog before you scan a new form.
The scanner must be connected, its power must be on, and the correct driver must be installed. Otherwise, the dialog displays default values and is disabled. See also Selecting a scanner.
The settings shown in the dialog have nothing to do with any form definition currently open. They apply to all new form definitions until you change the settings or close the Manager.
Normally, only form definitions with the same scanner settings can be run together in the same Scan job. (More info.)
If a form definition has the wrong scanner settings, one possible solution is to rescan the form.
ScanAhead affects which commands should be selected in the Operator control dialog when Scan finds an unidentified form and stops.
Advanced scanner settings: Kofax or ISIS
Checking the scanner settings of a form definition