MySQL Entity Framework Error - The specified store provider cannot be found in the configuration, or is not valid

But it only works on PCs that have had the "MySQL Connector Net 6.4.4" installed.

Does it mean that you are trying to run your code on machine where the provider is not installed? In such case you must also register the provider in your configuration file because installation adds it to machine.config and if you didn't install it the provider is currently not registered.

Try to add this to your web.config file:

<system.data>
  <DbProviderFactories>
    <add name="MySQL Data Provider" 
         invariant="MySql.Data.MySqlClient" 
         description=".Net Framework Data Provider for MySQL"  
         type="MySql.Data.MySqlClient.MySqlClientFactory, MySql.Data, Version=6.4.4.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d" />
  </DbProviderFactories>
</system.data>

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.

Add this in web config

 <system.data>
    <DbProviderFactories>
      <remove invariant="MySql.Data.MySqlClient" />
      <add name="MySQL Data Provider" invariant="MySql.Data.MySqlClient" description=".Net Framework Data Provider for MySQL" type="MySql.Data.MySqlClient.MySqlClientFactory,MySql.Data" />
    </DbProviderFactories>
  </system.data>

For people that reach this old question via Google like I did:

You will also get this error if you upgrade to MySQL for Visual Studio 1.1.3, which is the first compatible version with Visual Studio 2013, but still use MySQL Connector 6.6.6, which as far as I know is the last version that was compatible with Entity Framework 4.3.1.

We knew we had to update to EF5 (or 6) ASAP, but now this is forcing the change upon us at a very inconvenient time...