Error 3 Error 5: The ‘Namespace’ attribute is invalid – The value ‘‘ is invalid according to its data type ‘http://schemas.microsoft.com/ado/2008/09/edm:TNamespaceName’ – The Pattern constraint failed.
This error may come up when you try to add a new blank “Ado.Net Entity Data Model” to your project and name the EDM with a character line _(underscore),-(hyphen), etc. in the name. I got this for this two values and there must be more.
The way to solve this error is to name the EDM without any special character in it.
This is for the records J