Hi,

as we all know, there are three types of Calendars in MS PROJECT 2016: Base Calendars, Resource Calendars and Task Calendars. they are prioritized in that order (from low to high importance), which means that Task Calendar has  the highest priority. When we are talking about Resource Calendars, we all know why and when to use it. For example, if 12 resources has a common days off, or working hours, we will create Resource Calendar and assign it to those resources. But why to use Task Calendar? Let’s suppose that we have few (or many) Tasks that should be, for example, done in a certain location. And that this location is for some reason available to work at only from Monday to Wednesday, and that it can not be work at Thursday and Friday. for those Task we will have to create Task calendar and Assign it to those, specific Tasks.

Let’s go.  I will first create a new Project:

For  Special Tasks I will create separate Calendar, and I will call it MON-WEN:

and then:

and then:

Finally I will assign this Calendar to the Special Task, and I will get:

Finally I will get:

As you can see in Information column I have a notice that those Tasks has specific calendar, and Finish date is moved.

Now let’s suppose that we have John as Resource who is able to work only at Thursday and Friday:

What will happened if I try to assign John to the Special al Task?

As you can see, I can not do it. Why? Because John is supposed to work at Thursday and Friday, and Task should be worked on only at Monday to Wednesday. If I now change the option mentioned above, I will get:

and:

As you can see, John is now allocated to this Task, but it is show as over allocated, because this is conflict with his Calendar. So he will work to this Task, even he is not supposed to. Now, finally, in this example we should as ourselves a question: “But what if John is really not available from Monday to Wednesday?”.  Well in this situation you will not assign it to the Task. So what are our options? Only two of them. Find another resource who will be available to work from Monday to Wednesday on those Tasks, or change Task Calendar (so make this location available on Thursdays and Fridays). If those are not options, then you are not going to be able to do the Task. As simple as that. Remember, MS Project is a tool. Real life is something else.