visual studio 2015 update 1 Oracle ADO.NET provider is either not registered, or could not be loaded

I'm developing an application using Visual Studio 2015 and Framework version 4.6 with Entity Framewrok 6 and Oracle Database. Every thing was working fine until today after installing the visual Studio 2015 update 1. I couldn't build the application and I'm getting the following Error Message:

ADO.NET provider with invariant name 'Oracle.ManagedDataAccess.Client' is either not registered in the machine or application config file, or could not be loaded.

I tried restoring packages, removing the Oracle packages (DataAccess and EntitFrameWork) and adding them again with no success. I also found this slightly similar issue in Oracle community but the guy had to uninstall Visual Studio to solve the issue.