Robohelp 11 - Publishing webhelp to the 'merged projects' folder does not create a masterdata.xml file

Using Robohelp 11, when publishing webhelp to the 'merged projects' folder, a masterdata.xml file is not created.  When I then open the html file to read the help text I just created, there is an error message on screen stating 'unable to read masterdata.xml.

Does anyone know what creates the masterdata.xml file when publishing help files to the merged projects folder please?

Any suggestions would be greatly appreciated.