Project: Manual Calculation Produces Unexepected Results
  
PSS ID Number: Q104750
Article last modified on 03-15-1995
 
3.00 3.00a | 3.00
 
WINDOWS    | MACINTOSH
 

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The information in this article applies to:
 
 - Microsoft Project for Windows, versions 3.0, 3.0a
 - Microsoft Project for Macintosh, version 3.0
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SYMPTOMS
========
 
Microsoft Project may calculate your project differently than expected
when calculation is set to manual instead of automatic.
 
CAUSE
=====
 
When Microsoft Project has at least two summary tasks that are linked
and when a predecessor to the first summary slips, manual calculation
gives a different schedule than auto calculation. This assumes that
the child tasks to the first summary have completed. How the
Auto-split tasks option is set is unimportant.
 
WORKAROUND
==========
 
If your project has tasks that fit the pattern described above, you
will need to set calculation to automatic in order to have Microsoft
Project correctly calculate your project.
 
STATUS
======
 
Microsoft has confirmed this to be a problem in the Microsoft products
listed at the beginning of this article. We are researching this problem
and will post more information here in the Microsoft Knowledge Base as it
becomes available.
 
MORE INFORMATION
================
 
Steps to Reproduce Behavior
---------------------------
 
1. From the Options menu, choose Calculation and select Auto
   Calculation.
 
2. Enter 5 tasks, T1 through T5 (with default of 1 day duration).
 
3. Demote tasks T3, and T5 (T2 and T4 are summary tasks).
 
4. Select tasks T1 and T2. From the Edit menu, choose Link Tasks.
 
5. Select tasks T2 and T4. From the Edit menu, choose Link Tasks.
 
6. Select task T3. From the Edit menu, choose Form. In the % Complete
   field, type "100" (without the quotation marks) and choose OK.
 
7. Increase the duration of task T1 to 3d.
 
At this point, the second summary task is scheduled to the next
working day after the finish of the first summary; exactly where it
should be (this would cause negative slack if auto split tasks were
set to no).
 
8. From the Options menu, choose Calculation. Choose Manual
   Calculation.
 
9. From the Options menu, choose Project Info and choose OK.
 
10. From the Options menu, choose Calculate Now.
 
The second summary task is scheduled as if the first summary had
slipped in relation to T1, this relationship is incorrect.
 
KBCategory: kbusage
KBSubcategory:
 
Additional reference words: 3.00 3.00a
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Copyright Microsoft Corporation 1995.
