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Fix Incorrect Summary Task Dates When Importing P6 XML to Project

Huda Qurayshi Sep 27, 2026 869 views

Question details

The user needs to correct summary task dates in Microsoft Project that fail to align with their respective subtask dates after importing an XML file exported from Oracle Primavera P6.

Fix Incorrect Summary Task Dates When Importing P6 XML to MS Project

Product: Microsoft Project, Oracle Primavera P6
Device & OS: not provided
Scenario: Importing a project schedule via an XML file exported from Oracle Primavera P6 into Microsoft Project.
Observed behavior: Summary task dates in Microsoft Project do not reflect the dates of their subtasks, even with automatic scheduling and calculation enabled.

Before you start

Verify your current Microsoft Project version to rule out recent application update bugs, and double-check that automatic calculation is enabled before troubleshooting the XML import.

Solution 1Recommended

Remove Duplicate Predecessor Relationships in Primavera P6

Microsoft Project cannot correctly process duplicate predecessor relationships. Removing them in P6 before exporting the XML file resolves the summary task date calculation errors.

When importing an XML file from Oracle Primavera P6, duplicate predecessor relationships can cause Microsoft Project to miscalculate summary task dates. Microsoft Project generally does not accept multiple dependency types (like having both a Start-to-Start and a Finish-to-Finish dependency) between the exact same tasks.

Attempting to fix this by saving the file as an MPP and converting it back to XML will not work, as the underlying relationship data remains flawed. The issue must be corrected directly within the source P6 file.

Open project in P6

Launch Oracle Primavera P6 and open the specific project you intend to export.

Identify duplicate predecessors

Review the task dependencies and identify any tasks that have duplicate predecessors assigned (e.g., both 1960SS and 1960FF linking the same two tasks).

Remove duplicate dependencies

Delete the duplicate or conflicting relationships so that only one valid, driving predecessor dependency remains for those tasks.

Export the XML file

Navigate to 'File' > 'Export', select 'XML' as the format, and export the corrected project schedule.

Import into Microsoft Project

Open Microsoft Project, go to 'File' > 'Open', select the newly generated XML file, and verify that the summary task dates now accurately reflect the subtasks.

Remove Duplicate Predecessor Relationships in Primavera P6

Check MS Project Version: If the issue persists after removing duplicates, check whether the problem began after a recent Microsoft Project update (e.g., Project 2024 or Project Online desktop client) to see if a version rollback is required.

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Frequently Asked Questions

Why do summary task dates not match subtasks in Microsoft Project?

This typically happens if automatic scheduling is turned off, or if imported data contains conflicting dependency rules, such as duplicate predecessors that Microsoft Project cannot calculate properly.

Can Microsoft Project handle multiple predecessor relationships between the same tasks?

Generally, no. Microsoft Project does not handle duplicate predecessor relationships well (e.g., having both Start-to-Start and Finish-to-Finish dependencies for the same tasks). It is best practice to keep only the primary driving relationship.

How do I fix P6 XML import calculation errors in Microsoft Project?

To fix import calculation errors, you should first clean up the schedule in Primavera P6 by removing duplicate relationships, then re-export the XML file, and import it fresh into Microsoft Project.

Does saving the imported file as an MPP and re-importing the XML fix the dates?

No, saving as MPP and converting back to XML retains the underlying data errors, such as duplicate predecessors, which cause the calculation issue. The root cause must be resolved in Oracle Primavera P6 before exporting.

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