PRJ98: Incorrect Slack and Critical Path with FNET Constraint (192027)
The information in this article applies to:
- Microsoft Project 98 for Windows
This article was previously published under Q192027 SYMPTOMS
In Microsoft Project 98, when you link tasks or assign a Finish No Earlier
Than (FNET) constraint, tasks may show incorrect slack and may incorrectly
display as noncritical. You may also receive the following scheduling error
message:
Task <task name and number> cannot be completed in the time allocated
because there is a scheduling conflict between this task and another to which it is linked.
CAUSE
This behavior may occur when you link or assign a Finish No Earlier Than
(FNET) constraint to tasks and the following conditions are true:
- Two or more tasks have a Finish-to-Finish (FF) relationship.
- Two or more tasks have a Start-to-Start (SS) relationship.
- One or more tasks have a Finish No Earlier Than (FNET)
constraint.
Slack is incorrectly calculated in a project that is scheduled from start,
if you combine an FNET constraint with a chain of tasks that have FF and SS
relationships. Conversely, slack may be incorrectly calculated in a project
that is scheduled from finish, if you use a Start No Earlier Than (SNET)
constraint.
Consider the scheduling of the following tasks where the project is
scheduled from the start date:
ID Name Duration Predecessor
--------------------------------
1 Task1 1d
2 Task2 1d 1FF
3 Task3 2d 2SS
If you place a FNET constraint on Task2, both Task1 and Task 2 incorrectly
show slack.
WORKAROUND
To work around this behavior, use a constraint other than Finish No Earlier Than or Start No Earlier Than, if possible.
STATUSMicrosoft has confirmed that this is a problem in the Microsoft products that are listed at the beginning of this article.
| Modification Type: | Major | Last Reviewed: | 10/17/2002 |
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| Keywords: | kbbug KB192027 |
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