Cadence ProjectMaster 4.0 now supports import and export with Microsoft Project 2010, in addition to versions 2007 and 2003. Microsoft has changed the import and export format for version 2010 from the older ".mpx" format to a standard ".xml" format. As a result, your Windows system defaults may not operate as expected when importing and exporting with Project 2010.
To ensure import and export continues to function normally with Project 2010, right-click on the ProjectMaster 4.0 ".xml" export file. Select "Open with..." and choose Microsoft Project 2010. If you would like to ensure Microsoft Project 2010 is the default target the next time you export from ProjectMaster 4.0, make sure to select "Set as default" in the Project 2010 import dialog.