Could not load file or assembly EntityFramework after downgrading EF 5 0 0 0 -- 4 3 1 0

Question

After too hastily upgrading to EF 5 0 0 0 RC and being stuck with a  NET 4 5 project that wouldn t deploy to Windows Azure   NET 4 0 and below   I decided to downgrade to EF 4 3 1 0   I m unsure of the best way to perform this type of migration but my strategy is to use  Manage NuGet Packages  identify which projects reference the package  uncheck the package from each project  install the replacement and recheck the correct projects   Unfortunately  after doing this  my solution produced the titular  FileLoadException    Could not load file or assembly  EntityFramework  Version 5 0 0 0  Culture neutral          PublicKeyToken b77a5c561934e089  or one of its dependencies  The located assembly s  manifest definition does not match the assembly reference   Exception from HRESULT  0x80131040    I searched through the solution files particularly packages config for references to EF 5 0 0 0 RC but could find none

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public Configuration         AutomaticMigrationsEnabled   false          register mysql code generator      SetSqlGenerator  MySql Data MySqlClient   new MySql Data Entity MySqlMigrationSqlGenerator         I find out that connector 6 6 4 will not work with Entity Framework 5 but with Entity Framework 4 3  So to downgrade issue the following commands in the package manager console   Uninstall-Package EntityFramework  Install-Package EntityFramework -Version 4 3 1   Finally I do Update-Database -Verbose  again and voila  The schema and tables are created  Wait for the next version of connector to use it with Entity Framework 5

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In your references click on the EntitiyFramework   Go to properties and set the specific version to False  It worked for me

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I have this issue  and all I did was make sure that I was referencing the right  Net framework in all the projects then just change the web config from   From    lt section name  entityFramework  type  System Data Entity Internal ConfigFile EntityFrameworkSection  EntityFramework  Version 5 0 0 0  Culture neutral  PublicKeyToken b77a5c561934e089  requirePermission  false   gt    To    lt section name  entityFramework  type  System Data Entity Internal ConfigFile EntityFrameworkSection  EntityFramework  requirePermission  false   gt    All works

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After failed attempts to find references to EntityFramework in repositories config and elsewhere  I stumbled upon a reference in Web config as I was editing it to help with my diagnosis   The bindingRedirect referenced 5 0 0 0 which was no longer installed and this appeared to be the source of the exception  Honestly  I did not add this reference to Web config and  after trying to duplicate the error in a separate project  discovered that it is not added by the NuGet package installer so  I don t know why it was there but something added it    lt dependentAssembly gt     lt assemblyIdentity name  EntityFramework  publicKeyToken  b77a5c561934e089  culture  neutral    gt     lt bindingRedirect oldVersion  0 0 0 0-5 0 0 0  newVersion  5 0 0 0    gt   lt  dependentAssembly gt    I decided to replace this with the equivalent element from a working project  NB the references to 5 0 0 0 are replaced with 4 3 1 0 in the following    lt dependentAssembly gt     lt assemblyIdentity name  EntityFramework  publicKeyToken  b77a5c561934e089  culture  neutral    gt     lt bindingRedirect oldVersion  0 0 0 0-4 3 1 0  newVersion  4 3 1 0    gt   lt  dependentAssembly gt    This worked   I then decided to remove the dependentAssembly reference for the EntityFramework in its entirety    It still worked   So  I m posting this here as a self-answered question in the hope that it helps someone else  If anyone can explain to me    What added the dependentAssembly for EntityFramework to my Web config Any consequence s  of removing these references   I d be interested to learn

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If you used the Visual Studio 2012 ASP NET Web Forms Application template then you would have gotten that reference  I m assuming it s the one you would get via Nuget instead of the framework System Data Entity reference

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While Building a Project  if in the project properties it shows that it is build under Target NET Framework 4 5  update it to 4 6 or 4 6 1   Then the build will be able to locate Entity Framework 6 0 in the Web config file  This approach solved my problem   Selecting Target framework from Project Properties

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I had the same issue when updating an older project  Here s what I did to resolve it    Converted all projects to  NET 4 5  Uninstalled the NuGet package for Entity Framework 5  Reinstalled the NuGet package for Entity Framework 5  Cleaned the solution  Rebuilt the solution    The projects that used Entity Framework 5 and  NET 4 were installing the Entity Framework dll version 4 4   Once I switched the  NET version to 4 5 on the project  the dll version would be 5   My problem came from older projects being on  NET 4 and a newer project running  NET 4 5 so there were 2 dll versions of EF in my solution   Hope this helps someone

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I had a similar issue    On my ASP NET MVC project  I ve added a Sql Server Compact database  sdf  to my App Data folder  VS added a reference to EntityFramework dll  version 4     The web config file was updated appropriately with the 4   configuration    lt section name  entityFramework  type  System Data Entity Internal ConfigFile EntityFrameworkSection  EntityFramework  Version 4 4 0 0  Culture neutral  PublicKeyToken b77a5c561934e089  requirePermission  false   gt  I ve added a new project to my solution  a Data Access Layer project   Here I ve added an EDMX file  VS added a reference to EntityFramework dll  version 5 0  The App config file was updated appropriately with the 5 0 configuration   lt section name  entityFramework  type  System Data Entity Internal ConfigFile EntityFrameworkSection  EntityFramework  Version 5 0 0 0  Culture neutral  PublicKeyToken b77a5c561934e089  requirePermission  false    gt    On execution  when reading from the database the app always thrown the exception Could not load file or assembly  EntityFramework  Version 5 0 0 0       The issue was fixed by removing the EntityFramework dll v4 0 from my MVC project  I ve also updated the web config file with the correct 5 0 version  Then everything worked as expected

User · Answer

I got same issue  I was getting the System Data Entity Infrastructure  error which is only part of v5 0 or later  Just right click the Reference and select  Manage NuGet Package    In the Installed Package option   uninstall the Entity FrameWork which is already installed and Install the 5 0 version  It solve the problem  I was trying manually get the System Data Entity reference   which was not success

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I received the exact same error message   Except that my error message said  Could not load file or assembly  EntityFramework  Version 6 0 0 0      because I installed EF 6 1 1   Here s what I did to resolve the problem   1   I started NuGet Manager Console by clicking on Tools   NuGet Package Manager   Package Manager Console 2  I uninstalled the installed EntityFramework 6 1 1 by typing the following command   Uninstall-package EntityFramework   3  Once I received confirmation that the package has been uninstalled successfully  I installed the 5 0 0 version by typing the following command   Install-Package EntityFramework -version 5 0 0   The problem is resolved

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I had a similar issue running unit tests using MSTEST under Jenkins  The fix in my case was to remove  Version 6 0 0 0    as shown below   Old       lt section name  entityFramework  type  System Data Entity Internal ConfigFile EntityFrameworkSection  EntityFramework  Version 6 0 0 0  Culture neutral  PublicKeyToken xxxx  requirePermission  false    gt   New       lt section name  entityFramework  type  System Data Entity Internal ConfigFile EntityFrameworkSection  EntityFramework  Culture neutral  PublicKeyToken xxxx  requirePermission  false    gt    I had to make this change is several App config and Web config files in my multi-project solution

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I had similar issue with selenium  I downgraded my selenium using NuGet and got the same error message  My solution was to remove the newer version lines from the app config file

[entity-framework] Could not load file or assembly 'EntityFramework' after downgrading EF 5.0.0.0 --> 4.3.1.0

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