I have a task with fixed duration that must finish by a certain date.
It has several predecessors. If I schedule it manually (start and finish date) it obviously works OK, but I would rather schedule it with just a finish date and ask to schedule ALAP. (That way if the constraint date changes, the start date and all predecessors will update accordingly, without me having to remember to also change the start date.)

I have tried setting with a deadline and ALAP, but it schedules the task to finish two weeks before the deadline (even if I delete all predecessors). Why? Does the deadline not affect scheduling at all? Is there any way I can schedule it to finish on my deadline?


The deadline does not affect schedule at all. It only marks a date that the task should finish at. If the tasks is delayed and its finish date is later than the deadline, a red sign appears in the info column indicating that the task did not meet the deadline, but that's it.

Adding an ALAP constraint will move the task as late as possible, WITHOUT AFFECTING THE CURRENT PROJECT FINISH DATE. The task will move until its finish date is the same as the project's finish date. If this is the last task of the project, it will not move at all.

If you want to force the task to finish in a certain date, you need to set a "Finish no earlier than..." constraint with the finish date you want. Actually, you can achieve exactly the same result by modifying the task's finish date manually.

  • Thanks @Francisco, I see now the effect of the Project Start or Finish constraining these task. I don't have a specific start and finish in mind, I am exploring possibilities, so it is a bit limiting to be constrained by one or the other - I suppose the "Finish no earlier than" option will help me manage that. – James Nov 13 '17 at 4:13
  • 1
    On another note, I did find that if a deadline was within the project timeline, ALAP did use the Deadline as a constraint (but not if the Deadline fell outside the Project finish). – James Nov 13 '17 at 4:15
  • Interesting... I didn't know that Deadline was considered in an ALAP constraint. You are right, if the project finish date is earlier than the deadline, then the ALAP will constraint to the project finish date. – Francisco Alcalá Nov 24 '17 at 4:59

If your auto-scheduled task with ALAP constraint AND a deadline is being scheduled to finish two weeks before the deadline, then it has successors that are preventing it from being delayed further. That is, further delay of the task will cause one of the following to occur: a later constraint or deadline will be violated; or a relationship to a manual task will be violated; or the project completion will be delayed.

  • In this case I had no subsequent tasks; the task in question is the final task in the sub-project. – James Oct 31 '17 at 5:30
  • Absent logical successors, then check for hierarchical successors. Specifically, any higher-level outline task that is manually scheduled, constrained, deadlined, or has logical successors of its own. – Tom Boyle Oct 31 '17 at 11:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.