Hi,

today I will show you what happens wen you have Fixed Duration Tasks with Resources assigned to them, and those resource are unavailable at the specific time. I will use MS PROJECT 2016

First I will create simple Project with two Tasks (both Fixed Duration Type):

As you can see, both Tasks has 3 days Duration. I added two more columns to the Gantt Chart View: Work, and Type!

Now I will create two Resources, John and Mary, and I will put for Mary Vacation (e.g. non working time) from 11.06.2018 to 17.06.2017:

Finally, I will assign John to the Task 1, and Mary to the Task 2:

As you can see Work for the Task 1 is 40 hours (as expected), but for the Task 2 it is 0 hours. How is it possible? Even if this does not make a sense it is possible because Task has fixed duration, so it is supposed to be worked on from Monday 11.06.2018 to Friday 15.06.2018, and the Resource is unavailable at that specific time. So, when you assign Resource to the Task which is Fixed Duration type be aware and careful on that.

Now, let’s say that, for some reason Task 1 will have 7 days Duration instead of 5:

Now, as we know, Mary is on her Vacation from 11.06.2018 to 17.06.2017, and Task 2 has now Duration from 12.06.2018 to 19.06. So Mary is available at Monday 18.06.2018, and Tuesday 19.06.2018, but the work for her is still 0 hours.

Now I will put Duration for Task 1 at 1 day:

You can see that nothing has changed in work for Mary in this example either.

Maybe you have expected that work should be calculated for those days in which Mary is available, but it is not. Well, it is not calculated automatically.  But if he is unassigned from the Task and assigned again, then you will have what you have expected:

Now you can see that Mary will work from Tuesday 05.06.2018 to Friday 08.09.2018 (e.g. total 32 hours), and next Monday, 11.06.2018 she will not, because she is on Vacation and therefore not available.

Be aware of this:

1. When you assign a Resource to the Fixed Duration Type, work will be calculated according to available time of that specific resource during specific Task period.
2. If the Resource is unavailable to the Task for the whole Duration of the Task (e.g. Work is 0 hours), you will not get any warning from MS PROJECT
3. If Start date of the Task is moved for any reason for the Task and Resource is became available for it (for specific or whole duration), MS PROJECT will NOT recalculate work for Resource! It will remain 0. So for this you should reassign same resource to the Task.

Regards!