Hi,
Again, I have a question from one of my Blog readers:
“Nenad,
I’m new to MS Project and really appreciate information on this site. I have a question regarding your post “Resource vs. Task Calendar in MS PROJECT 2013” posted on July 10, 2013.
Please explain how were you able to schedule the Task for your resource Nenad for Sat. 10/13 and Sunday, 10/14 even though both of those days were his working days?
Isn’t the MSP scheduling rule states that in order to schedule a task for an assigned resource, the task and the resource should have COMMON working days, unless the option to ignore resource calendar is selected.
In this case Saturday and Sunday of 10/13 and 10/14 respectively were set as working days for Nenad, bot set as non-working days for the task as it was using a Standard calendar with non-working Saturdays and Sundays.
Thank you,
Alex”
First I’m going to create Scenario for this Case in MS PROJECT 2016, and then I will explain it.
I will create brand new Project with one Task:
As you can see Task will start at Friday 11.03.2016, and since duration is 5 days it will end at Thursday 17.03.2016, because Standard Calendar is used, and weekend is non working time. You can see that here:
If you click on Saturday or Sunday, you will find that From and To field are empty, because those are non working days.
Now I will create John as Resource, and I will assign him to the Task:
and:
As you can see nothing has changed in Start and finish date. Now suppose that John is hard worker and he is supposed to work at Saturday, 12.03.2016, and Sunday 13.03.2016:
Now let’s see Task Usage View:
as you can see Finish date is now Tuesday, 15.03.2016, and John will work during the weekend.
Now, the question from my blog Reader is: WHY? Yes, Standard Calendar is set in a way that each and every Saturday and Sunday are non working days. BUT! If you create Resource in MS PROJECT, and you set a calendar for it (like I did, or in any other possible way), then RESOURCE CALENDAR has higher priority that Project Calendar. And it does make a sense. So, in my example, Project calendar says: “During weekend, work on Tasks will not be performed!”, but since John will work on the Task with exception (he can work on this particular weekend), MS PROJECT Says: “No matter on Project Calendar which says that during weekend work will not be performed on Tasks, for this particular Task John will work at weekend, because that is written in his instance of Project Calendar, and Task will end sooner!”
Remember: Resource calendar setup has higher Priority than Project calendar setup.
Hope this helps.
Regards 
Nenad Trajkovski 
Hi Nenad,
Thank you very mush. But can you please explain the following inconsistency in MSP behavior:
If in the example you just presented you change a task default calendar’s option None to Standard (Task Information>Advanced<Calendar), the resource John will no longer be scheduled to work on the weekend days 12/03/16 and 13/03/16, and the task will be scheduled as if no exception in John's calendar for these 2 days making them working for John was made at all, and the task will be finished on 17/03/16 instead 15/03/16.
Why? In my understanding the default task's calendar option None is referenced to a default Standard Project calendar, so why MSP behaves differently when you leave a default None for the task's calendar and when you select a Standard calendar instead, even though the two are exactly the same calendar- Standard Project Calendar?
Thank you,
Alex
My answer is on my post from today, 18.03.2016