Q128620 - Schedule Error in Task with Nonzero Delay Driven by ALAP Task

Schedule Error in Task with Nonzero Delay Driven by ALAP Task

Q128620

The information in this article applies to:

Microsoft Project for Windows, versions 3.0, 3.0a, 4.0
Microsoft Project for the Macintosh, versions 3.0, 4.0

SYMPTOMS

A task with nonzero delay may be scheduled incorrectly if the following conditions are true:

The project is scheduled from start.

The task with the nonzero delay has no direct predecessors with an ALAP constraint.

The task with the nonzero delay is "indirectly driven" by a task that has an ALAP constraint. (That is, a chain of successors runs from the ALAP task to the task with the nonzero delay, or to a summary task that contains it. None of the tasks involved has an actual start, and the linked tasks have only ASAP, SNET, or FNET constraints.)

Under these conditions, the start, finish, and total slack of the task with the nonzero delay, and any tasks it drives, may be calculated incorrectly. The Total Slack for these tasks may become negative, resulting in the scheduling message "Late date ..." or the equivalent Planning Wizard warning.

WORKAROUND

To work around this problem, make the ALAP task a predecessor of the problem task with the nonzero delay. If necessary, use negative lag in this workaround relationship so that it does not affect the original logic.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

Under the above conditions, the delay is correctly ignored when the late finish is calculated for the task with the nonzero delay; however, delay is incorrectly included when the task's finish is calculated. This inclusion of delay creates an amount of negative slack equal to the working time between the late finish and finish dates.

Additional query words: 3.00a

Keywords : kbusage
Issue type : kbbug
Technology : kbHWMAC kbOSMAC kbProjectSearch kbProject400Mac kbProjectMacSearch kbProject300Mac kbProject300 kbProject300a kbProject400