Project: Incorrect Late Start/Finish and Total Slack with SNET

MORE INFORMATION

When a task has a Start No Earlier Than constraint, but the constraint date is earlier than the currently scheduled date because the task has a start-to-start relationship with its successor, the late dates for the task are incorrect, causing the slack to be incorrect.

Note that this problem only affects late dates. The scheduled dates remain correct.

Steps to Reproduce Behavior in Microsoft Project 4.0

1. In a new project, enter three tasks, T1, T2, and T3.
2. From the File menu, choose Summary Info. In the Start Date box, type 3/1/94 and choose OK.
3. In the Duration column for tasks T2 and T3, type 2w.
4. Select T3, and choose Task Information from the Insert menu. Select the Predecessors tab. In the Task Name column, type T2, in the Type column, type SS and in the Lag column, type 1w. Choose OK.
5. Select T2, and choose Task Information from the Insert menu. Select the Predecessors tab. In the Task Name column, type T1 and choose OK.
6. From the View menu, choose More Views. From the Views list, select Task Sheet and choose Apply. From the View menu, choose Table, and then choose Schedule.
   
   Note that the Late Start date for T1 is 3/1/94 and for T2 is 3/2/94 with Free Slack and Total Slack both 0d.
7. Select T2, and choose Task Information from the Insert menu. Select the Advanced tab. From the Constraint list, select Start No Earlier Than. In the Date box, type 3/1/94 and choose OK.

The Late Start and Late Finish dates and the Total Slack for T1 and T2 are changed to the following:

Task Name	Late Start	Late Finish	Total Slack
t1	3/8/94	3/8/94	5d
t2	3/9/94	3/22/94	5d

Note that T1 and T2 are no longer critical tasks.