Microsoft Project data could be imported to Primavera P6 via the XML file format. Native MPP files should be saved as XML to generate importable format. Large projects (having hundreds of  activities and resource assignments) cause gigantic XML files of several hundreds of MBs.
Below application is for minifying the Microsoft Project XML files to be imported to Oracle Primavera P6. 

If you are struggling to import MS Project XML files which are too large, this application may help. This small application will:

• remove baseline column data (if desired. As baseline columns do not constitute a baseline in P6 terms)
• remove resource assignment time phased data
• truncate MS Project task names to Primavera P6 activity and WBS name field length
• eliminate some integrity violating data

You may expect a 10-50 times smaller XML file size after cleaning with this application especially with resource loaded projects.

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