How can I add Saturday and Sunday as working days in Microsoft Project?

Answer 1

One option would be the following:

1. Click on the Project tab
2. Click on 'Change Working Time'
3. Click on the 'Work Weeks' tab
4. Set Saturday and Sunday for 8am - 12pm / 1pm - 5pm (these are the default work times in MS Project)
5. Click OK and you should see Saturday and Sunday no longer greyed out
6. Click OK one last time and the standard calendar has been made a 7 day work week

I usually make separate calendars as required to support situations like this in my schedules. But this is the quick way to do it if all of your tasks are intended to be using a 7 day work week...