The entry '' has already been added error

Question

I have a web.config in ASP.net giving me configuration error.

Answer 1

You should use when adding any providers to your web.config. Read this article: http://weblogs.asp.net/scottgu/archive/2006/11/20/common-gotcha-don-t-forget-to-clear-when-adding-providers.aspx

The root cause of the above problem rests in how the new provider was registered within the web.config file.

The section within the web.config file is implemented as a collection, and so it is possible to register multiple providers at the same time

If you have another project using the same connection string name you will receive this error because that connection string has already been added to the collection.