I have a project with a number of similar tasks all with slightly different durations. The tasks are also broken down into sub-tasks (all the sub-tasks are the same for each main task, again only with slightly different durations). I have set up all the relationships Finish-to-Start - each task starts after the other finishes (ASAP). I have also set up the calendar to work 8am to 6pm in this case. All tasks are currently autoscheduled.

The main tasks are all between 2 and 3 hours in duration. I would like to set up the project so that main task will not start unless it can also be completed within the same shift (i.e. all the subtasks must be finished within one shift and not straddle the night into the next day). Currently it is possible for a sub-task to be started at, say, 5pm on one day and finished at, say, 9am the next day. I can't have this in the type of project I am working on.

None of the constraints seem to be quite right for what I need, and deadlines are not exactly what I'm looking for either as I'd rather this be an automatic scheduling option rather than a check or other dependancy.

Is this possible in Microsoft Project? Any advice appreciated.

  • I do not believe it is possible to automatically set tasks to start on a day (or period) boundary rather than span period boundaries. If anyone has a solution I would love to know about it as this comes up every now and then...
    – Marv Mills
    Commented Apr 7, 2015 at 17:49
  • This may be possible but a couple of clarifying questions first: When you refer to "main tasks" do you mean summary tasks? So your detail tasks (subtasks) are how long in duration?
    – JulieS
    Commented Apr 8, 2015 at 13:27
  • From your description, this sounds like an extremely detailed task list. How long is your overall duration? Any possibility that you can eliminate the subtask details and just work with what you are calling "main tasks"?
    – JulieS
    Commented Apr 8, 2015 at 13:40
  • I could delete the subtasks and work only with the main tasks. Each main task is about 1.5hrs to 2hrs long. I'm not precious about the subtasks. Either way, the main task must be started and completed within the shift. Currently the only work around I have found is adding milestones at the end of each shift but this requires links which need re-adjusting when the order of tasks changes. It's been suggested I put milestones on each task and put the milestones on a different calendar. I'll try it and report back if it works.
    – Carin
    Commented Apr 8, 2015 at 16:09
  • To answer the other questions, yes, the 'main tasks' are summary tasks and there are 26 of them. Total duration around 8 working shifts currently.
    – Carin
    Commented Apr 8, 2015 at 16:10

1 Answer 1


If you can live with just the summary tasks, you can achieve what you are looking for with "buffer tasks" and two new base calendars. Before each of the main tasks, add a task with a one minute duration. Link that one minute "buffer" task to the main task. Add the buffer tasks before every main task (copy and paste works well). You cannot use milestones for buffers as milestones have zero duration and therefore will not obey a task calendar.

Then create two new base calendars. The first (2 hour) make the working time only 7:59 am to 3:59 pm every working day. The second (1.5 hours) make the working time 7:59 am to 3:29 pm.

Assign the 2 hour calendar to the buffer task before a main task whose duration is 2 hours. Because the calendar restricts working time to end by 4:00 pm the two hour task should be able to happen before 6:00 pm. If the task schedule pushes the buffer to after 4:00 pm - it will simply move to the beginning of the next working day. Assign the 1.5 hour calendar to the buffer tasks preceding any 1.5 hour main task. To make assigning the task calendars easier, add the Task Calendar column to the table.

Link your tasks and all should be better.

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