Force Main and Force SSP Recalc errors are caused by data changes in the system after the main calc has ran and the FPS has been created.
To prevent these errors:
Click Payroll then select Calculation Menu.
Select Workers Requiring Incremental Calc.
Complete the Force Main Recalc field.
Click Start.
Review the workers here, it tells you if they need an SSP or Main calc so that you can take the appropriate action for these workers before creating the FPS.