Products > PSOP > Documentation Why does PSOP say my requested finish date is impossible? Activity relationships, constraints, and durations affect the minimum possible schedule length. For example, consider a project with two activities: Write FAQ and Publish FAQ with the obvious finish to start relationship between the two. If writing the FAQ will take 10 days and publishing it will take 4 days, then the shortest possible schedule is 14 days. If the project starts on January 1 and you ask PSOP to create a schedule that finishes earlier than January 15, PSOP will warn that the requested finish date is impossible. In addition to relationships, Start on, start on or before, finish on, mandatory start, and mandatory finish constraints can also affect minimum schedule lengths. Back to FAQ