Change the Constraint Type

Using constraints, you can control the start or finish date of important tasks. Microsoft Project automatically assigns the As Soon As Possible constraint when you enter a task. You should set other constraints only when necessary, such as when a client or contract requires that a task begin or end by a specific date.

Task constraints can help you create a more accurate schedule using detailed information. But constraints can also limit your schedule’s flexibility. If there’s a scheduling conflict between a constraint and a task dependency, Microsoft Project may schedule the task according to the constraint.

At various stages in your project, you may want to check the constraints on tasks in your schedule, particularly the tasks on the critical path, to make sure they remain necessary. Any constraint that requires you to enter a date should be applied carefully. Microsoft Project may recalculate the start and finish dates of a task with a flexible constraint, such as the Start No Earlier Than constraint. But fixed-date constraints, such as the Must Start On constraint, prevent Microsoft Project from recalculating the start and finish dates if the schedule changes. Fixed-date constraints also limit your ability to level overallocated resources.

For more information about why you should use constraints cautiously, see Chapter 6, "Tying Tasks to Specific Dates."

To examine constraints on tasks

1. On the View Bar, click Gantt Chart .
2. On the View menu, point to Table, and then click More Tables.
3. In the Tables list, click Constraint Dates, and then click Apply.
4. Scroll to the right to view the Constraint Type and Constraint Date fields.

If a task must start or finish in relation to a specific date, you can change its constraint from the default (As Soon As Possible) or change it back to As Soon As Possible.

To change a constraint

1. On the View Bar, click Gantt Chart .
2. In the Task Name field, select the task for which you want to change the constraint, and then click Task Information .
3. Click the Advanced tab, and then click a constraint in the Type box.
4. If the constraint requires a date, enter a constraint date in the Date box.
   If you don’t enter a date, Microsoft Project uses the current date as the constraint date.
   Microsoft Project recalculates the start and finish dates of all tasks affected by the change.

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