Unable to build file '<filename>', PackageAs property must be Default for files in a merge module project
The merge module project cannot be built because the PackageAs property for the referenced file is set to vsdpaLoose. Merge modules cannot contain loose files; all files must be packaged in the merge module.
To correct this error
Double-click the error message in the Task List to go to the file in the File System Editor.
In the Properties window, select the PackageAs property and choose vsdpaDefault.