There are multiple machine.config files in your \Windows\Microsoft.net\Framework\vXXXX\Config directories. Check both of the v2 and v4 machine.config files for the following (four files total you’re looking at here).
There was an EXTRA, self terminated <DbProviderFactories> tag in two of my files. I had all four open at once comparing them, and noticed in two of them, the V4 I believe, but check them all. Essentially it was like this and very easy to miss:
<add name=”Odbc Data Provider” invariant=”System.Data.Odbc” … />
<add name=”OleDb Data Provider” invariant=”System.Data.OleDb” … />
<add name=”OracleClient Data Provider” invariant=”System.Data … />
<add name=”SqlClient Data Provider” invariant=”System.Data … />
<add name=”IBM DB2 for i .NET Provider” invariant=”IBM.Data … />
<add name=”Microsoft SQL Server Compact Data Provider” … /></DbProviderFactories>
Notice the CLOSING tag at end of the <DProviderFactories> last item, in this case the “Microsoft SQL Server Compact Data Provider”, and then there’s another SELF CLOSING <DBProviderFactories> tag. Clean this up by keeping the one after the last item and deleting the self closing one at the end.
I rebooted, walked away, came back and it worked . . . so be SURE to reboot, walk away and come back or might not work.