If you have MySQL Connector/Net installed and then install Orcas (Visual Studio 2008) Beta 2 (and probably earlier versions), your machine.config file will be changed so that it does not include the MySQL Connector/Net data provider information anymore. This can lead to problems with the DataSet designer, first complaining about the MySQL Connector/Net and then with the message quoted in title of this post. The simple solution is to reinstall the MySQL Connector/Net which will put the necessary provider information back in the <system.data> section of your machine.config and your designers should start working normally again. Hope it helps.