hello.

3 questions, on the same thing:

1-i entered actual start and finish dates for an activity, that took place in the past. the duration cell calculated the duration and wrote the number of days between those days there, but with a question mark near it. lets say 40 days. so it displayed "40 days?" why was there a question mark? this did it in 2007 version, but when i tried 2010 version, it didnt display that question mark by the way.

2-and then, after entering those actual start and finish dates, just to see whats going to happen, i entered 41 days to duration manually. the question mark was now gone, but strangely, the actual finish date disappeared and it said NA. why?

3-also, when i entered 39 days, instead of 40 days, this time the actual finish date did not disappear, but it pulled itself backward, to reflect the shorter duration. why?