Hi,
Thank you for contacting Aspose support team.
I have tried to re-produce the issue with following sample code using Aspose.Tasks for .NET 17.3.0 but could not re-produce the issue. Could you please give a try to the sample code and share the feedback. If it is not as per your scenario, please modify it or provide your sample console application which can be compiled and executed here for re-producing the scenario. Also send any template MPP file which is used for creating the MPP file. It will help us to observe the issue and provide assistance accordingly.
Project proj = new Project(@“blank2010.mpp”);
Calendar cal = proj.Calendars.Add("TestCal");
proj.Set(Prj.Calendar, cal);
List<WorkingTime> wt = new List<WorkingTime>()
{
new WorkingTime() { FromTime = new DateTime(1,1,1,8, 0, 0), ToTime = new DateTime(1,1,1, 13, 0, 0) },
new WorkingTime() { FromTime = new DateTime(1,1,1,14, 0, 0), ToTime = new DateTime(1,1,1, 17, 0, 0) },
};
WeekDay mon = new WeekDay(DayType.Monday, wt);
WeekDay tue = new WeekDay(DayType.Tuesday, wt);
WeekDay wed = new WeekDay(DayType.Wednesday, wt);
WeekDay thu = new WeekDay(DayType.Thursday, wt);
WeekDay fri = new WeekDay(DayType.Friday, wt);
cal.WeekDays.Add(mon);
cal.WeekDays.Add(tue);
cal.WeekDays.Add(wed);
cal.WeekDays.Add(thu);
cal.WeekDays.Add(fri);
Task tsk1 = proj.RootTask.Children.Add("Task 1");
tsk1.Set(Tsk.Start, new DateTime(2017, 5, 21, 8, 0, 0));
tsk1.Set(Tsk.Finish, new DateTime(2017, 12, 21, 8, 0, 0));
proj.Recalculate();
proj.Save(@"output.mpp", SaveFileFormat.MPP);