Assembly Binding Old Reference Exception

Question

I have been trying to solve an assembly binding issue for the last 12 hours, with not much luck. Last week, I had upgraded all of the projects in a solution from EF 4.1.0.0 to EF 4.3.1.0. I added some tests this morning to an existing test project, cleaned and recompiled the solution. All the projects compile with no warnings or errors. At my entity framework call anywhere in the project, I receive the following exception:

Initialization method NutricityPPCTests.Common.DizzleProductExtensionsTests.TestSetup threw exception. System.IO.FileLoadException: System.IO.FileLoadException: Could not load file or assembly 'EntityFramework, Version=4.1.0.0, 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 fired up the fusion assembly binding log viewer, and found the log entry that corresponds to the exception. I have verified that my test project, the MOMData project both are referencing the correct EF4.3.1.0 assembly. I verified there were no references to EF 4.1.0.0 in the project files. I deleted the contents of the obj and bin directories in both projects. The project has been cleaned and rebuilt so many times, that my hard drive is probably going to give out tomorrow.

*** Assembly Binder Log Entry  (3/22/2012 @ 5:55:11 PM) ***

The operation failed.
Bind result: hr = 0x80131040. No description available.

Assembly manager loaded from:  C:\Windows\Microsoft.NET\Framework\v4.0.30319\clr.dll
Running under executable  c:\Program Files\Microsoft Visual Studio 10.0\Common7\IDE\QTAgent32.exe
--- A detailed error log follows. 

=== Pre-bind state information ===
LOG: User = NUTRICITY0\awolske
LOG: DisplayName = EntityFramework, Version=4.1.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
 (Fully-specified)
LOG: Appbase = file:///C:/Users/awolske/Documents/NutricityWorkspace/Nutricity/NutricityPPCTests/bin/Release
LOG: Initial PrivatePath = NULL
LOG: Dynamic Base = NULL
LOG: Cache Base = NULL
LOG: AppName = QTAgent32.exe
Calling assembly : MomData, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null.
===
LOG: This bind starts in default load context.
LOG: Using application configuration file: C:\Users\awolske\Documents\NutricityWorkspace\Nutricity\NutricityPPCTests\bin\Release\NutricityPPCTests.DLL.config
LOG: Using host configuration file: 
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.30319\config\machine.config.
LOG: Post-policy reference: EntityFramework, Version=4.1.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
LOG: GAC Lookup was unsuccessful.
LOG: Attempting download of new URL file:///C:/Users/awolske/Documents/NutricityWorkspace/Nutricity/NutricityPPCTests/bin/Release/EntityFramework.DLL.
LOG: Assembly download was successful. Attempting setup of file: C:\Users\awolske\Documents\NutricityWorkspace\Nutricity\NutricityPPCTests\bin\Release\EntityFramework.dll
LOG: Entering run-from-source setup phase.
LOG: Assembly Name is: EntityFramework, Version=4.3.1.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
WRN: Comparing the assembly name resulted in the mismatch: Minor Version
ERR: The assembly reference did not match the assembly definition found.
ERR: Failed to complete setup of assembly (hr = 0x80131040). Probing terminated.

Where else should I be looking for the old referenced assembly?!? Any help would be welcome, and greatly appreciated! Thanks in advance for your time!

Answer 1

Add the following to your web.config file:

<runtime>
<assemblyBinding>
        <dependentAssembly>
          <assemblyIdentity name="EntityFramework" publicKeyToken="b77a5c561934e089" culture="neutral" />
          <bindingRedirect oldVersion="0.0.0.0-4.3.1.0" newVersion="4.3.1.0" />
        </dependentAssembly>
   </assemblyBinding>
</runtime>

Answer 2

I had the same error. Most of the projects in my solution where referencing the Entity Framework 4.3.0.0 dll, but when I checked the references for all the projects in my solution, I found some projects referencing the Entity Framework 4.1.0.0 dll. Removing and replacing them with new references to the Entity Framework 4.3.0.0 dll fixed the problem.