I have written an assembly in C# to perform all data access for a MySQL database. I have successfully used the assembly (a compiled dll) in my C# winform desktop application
I found I had this issue too when using the standalone .NET connector 6.6.5 installer.
To resolve, simply uninstall the standalone .NET connector installer, and install the mysql-community-installer, this installer lets you add/remove features to MySQL, and in it one of the features is the .NET connector that has Entity Framework support.
Once you use this connector all your MySQL EF issues go away.