Error - Schema File Not In Build
Explanation
The command (Validate Instance, Generate Instance, or Validate Schema) could not be performed because the Build Action property of the schema file is set to None, preventing this schema from participating in these commands.
User Action
Select the relevant schema file in Microsoft Visual Studio Solution Explorer, and then in the Properties window, change the Build Action property to a Compile. Then attempt the Validate Instance, Generate Instance, or Validate Schema command again.