Hi,
I have the following situation:
Task - 3days - 04/05/2015 - 06/05/2015

When I change the duration from 3 to 2 days, obviously the length of the bar chart reduces accordingly.
When I change the "Hours per day" from 8 to 12 in the File > Options> Schedule, Project recalculate the duration from 3 to 2days but the length of the bar chart remains unchanged, still stretching over 3 days instead of 2.

Can anyone explain to me why it is like that?
Thank you.

A change in the definition of "day" is only part of the process. You still need to change the number of working hours per day in Change Working Time.

Thanks Julie

You're welcome.