Note
The project file that is to be compiled must also be named using the HtmlHelpName value with a .HxS extension. The project file must exist in the folder specified in the WorkingFolder property.
Sandcastle Help File Builder Documentation
B2X0002: An HTML help base name must be specified
Error B2X0002: An HTML help base name must be specified
Cause
This error occurs if the HtmlHelpName property on the Build2xHelpFile build task has not been set or is set to an empty string.
Solution
Specify a valid name for the HtmlHelpName property on the Build2xHelpFile build task in the project file.