Could not load file or assembly or one of its dependencies

Open IIS Manager

Select Application Pools

then select the pool you are using

go to advanced settings (at right side)

Change the flag of Enable 32-bit application false to true.

For me, none of the other solutions worked (including the clean/rebuild strategy). I found another workaround solution which is to close and re-open Visual Studio.

I guess this forces Visual Studio to re-load the solution and all the projects, rechecking the dependencies in the process.

Try to clean Debug and Release folders in your solution. Then remove and add unity again.

Despite the original question being posted five years ago, the problem still persists and is rather annoying.

The general solution is thorough analysis of all referenced assemblies to understand what's going wrong. To make this task easier I made a tool (a Visual Studio extension) which allows selecting a .NET assembly (a .dll or .exe file) to get a graph of all the referenced assemblies while highlighting conflicting or missing references.

The tool is available in Visual Studio Gallery:

• VS 2022
• Other Versions

Example of output:

At 99% the Could not load file or assembly or one of its dependencies problem is caused by dependencies! I suggest you follow this steps:

1. Download Dependency Walker from http://www.dependencywalker.com/

2. Launch Dependency Walker and open the dll (in my case NativeInterfaces.dll)

3. You can see one or more dll with the error in red Error opening file...

4. It means that this dll is missing in your system; in my case the dll name is MSVCR71.DLL

5. You can download missings dll from google and copy in right path (in my case c:\windows\system32)

6. At this point, you must register the new dll in the GAC (Global Assembly Cache): open a DOS terminal and write:

    cd \Windows\System32
    regsvr32 /i msvcr71.dll
   

7. Restart your application

Microsoft Enterprise Library (referenced by .NetTiers) was our problem, which was in turn referencing an older version of Unity. In order to solve the problem we used the following binding redirection in the web.config:

<configuration>
    <runtime>
        <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
            <dependentAssembly>
                <assemblyIdentity name="Microsoft.Practices.Unity" publicKeyToken="31bf3856ad364e35" culture="neutral" />
                <bindingRedirect oldVersion="1.0.0.0-2.0.414.0" newVersion="2.1.505.0" />
            </dependentAssembly>
            <dependentAssembly>
                <assemblyIdentity name="Microsoft.Practices.Unity.Configuration" publicKeyToken="31bf3856ad364e35" culture="neutral" />
                <bindingRedirect oldVersion="1.0.0.0-2.0.414.0" newVersion="2.1.505.0" />
            </dependentAssembly>
        </assemblyBinding>
    </runtime>
</configuration>

Alternatively, you may want to just update the Enterprise Library to the latest version.

Following worked for me.

• Remove Temporary Files C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files
• Close VSTS and Open Again
• Remove and Add the same DLLs (Note: you add the same matching versions)

Check the Web.config/App.config file in your project. See if the version numbers are correct.

<bindingRedirect oldVersion="X.X.X.X-X.X.X.X" newVersion="X.X.X.X" />

This worked for me.

In solution explorer right click on project (not solution), in build tab choose Platform target : "Any CPU".

Sometimes packages have different versions specificed for AssemblyVersion and AssemblyFileVersion.

I had this situation for the unity:

• AssemblyFileVersion is a version used by NuGet package manager - v2.1.505.2
• AssemblyVersion is a version used by CLR - v2.1.505.0

You have to specify redirects using an AssemblyVersion attribute. In my example pictures 2.1.505.0 should be used instead of 2.1.505.2

<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
 <assemblyIdentity name="Microsoft.Practices.Unity" publicKeyToken="31bf3856ad364e35" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-2.1.505.0" newVersion="2.1.505.0" />
</dependentAssembly>
</assemblyBinding>

You can also check next materials: What are differences between AssemblyVersion, AssemblyFileVersion and AssemblyInformationalVersion?

I also got this terrible error and found a solution for this...

1. Right Click on the Solution name
2. Click Clean Solution
3. Restart Visual Studio
4. Goto project Properties >> Build
5. Change Configuration to Release
6. Start Debugging (F5)

1) , 2)

4) , 5)

Hope this will help you also.

I had the same problem i solved it via the instructions below:

1. open tools menu and select option
2. in options, window go to Projects and Solutions/Web Projects
3. check use the 64bit version of IIS ...

• Goto :Solution -> Package
• Click on Advanced Tab (Find below the page)
• Add your dll to additional assemblies(this way we can add external dlls in sharepoint).

Not sure if this might help.

Check that the Assembly name and the Default namespace in the Properies in your asemblies match. This resolved my issue which yielded the same error.

In my case in the bin folder was a non reference dll called Unity.MVC3 , i tried to search any reference to this in visual studio without success, so my solution was so easy as delete that dll from the bin folder.

Thanks Riddhi M. Following worked for me.

Remove Temporary Files C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files Close VSTS and Open Again Remove and Add the same DLLs (Note: you add the same matching versions)

Tried closing and re-opening VS as suggested but it didn't work out.

I had to change from MIXED PLATFORMS to ANY CPU.

You say you have a lot of projects in your solution ... well, start with one near the top of the build order. Get that one to build and once you figure it out you can apply the same fix to the rest of them.

Honestly, you probably just need to refresh your reference. It sounds like you either updated your version and didn't update the references, or it's a relative path issue if you keep your solution in source control. Just verify your assumptions, and re-add the reference.

if you are getting this error message by opening an application on you windows xp it mean first you have installed that app due to its not working without net framework 4 and service pack 3 . you installed both and again you are getting this error so you should reinstall that app again but first uninstall from add and remove

if this not work please dont abuse me . i am also a junior

Following worked for me.

• Remove Temporary Files C:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files
  • then right click on Temporary Asp.net Files>properties>security and give total control access to IIS and to all user runing my project

This issue happened to me where one of my dependent libraries was compiling a DLL with "Any CPU" when the parent library was expecting a compilation of "x64".

I had this today, and in my case the issue was very odd:

  <dependentAssembly>
    <assemblyIdentity name="Microsoft.Owin.Host.SystemWeb" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-3.1.0" newVersion="3.1.0.0" />
  </dependentAssembly>0.

Note the stray characters at the end of the XML - somehow those had been moved from the version number to the end of this block of XML!

  <dependentAssembly>
    <assemblyIdentity name="Microsoft.Owin.Host.SystemWeb" publicKeyToken="31bf3856ad364e35" culture="neutral" />
    <bindingRedirect oldVersion="0.0.0.0-3.1.0.0" newVersion="3.1.0.0" />
  </dependentAssembly>

Changed to the above and voila! Everything worked again.

Clean the solution and then right click on the project and select Package

Here increment the Assembly and Assembly file version and rebuild.

If that does not work,

1 - Open the solution in file Explorer.

2 - Close Visual Studio.

3 - Remove all bin and obj folders.

4 - Reopen the project and build it.

You have to delete Your appname.dll file from your output folder. Cleanup Debug and Release folders. Rebuild and copy to output folder regenerated dll file.

I "Set as Startup Project" the unloaded/unfound library/project.

Then deployed it.

It worked!

I think it couldn't found the .dll because it was not in the assembly at first.

Another possible cause: make sure you haven't accidentally given both of the projects the same assembly name in project properties.

My solution for .NET 4.0, using Enterprise Library 5, was to add a reference to:

Microsoft.Practices.Unity.Interception.dll

Look out for conflicting references. Even after a clean and rebuild, conflicting references will still cause a problem. My problem was between AForge and Accord. I removed both of the references, and re-added the references re-choosing the particular reference (particular to my case, just Accord).

In my case, none of the proposed answer worked.

Here is what worked for me:

1. Remove the reference
2. Rename the DLL
3. Import the reference again

The second step was important apparently as it did not work without it.