Could not load file or assembly or one of its dependencies

Question

I'm having another of these "Could not load file or assembly or one of its dependencies" problems.

Additional information: Could not load file or assembly 'Microsoft.Practices.Unity, Version=1.2.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

I have no idea what is causing this or how I could debug it to find the cause.

I've done a search in my solution catalogs .csproj files, and every where I have Unity I have:

Reference Include="Microsoft.Practices.Unity, Version=2.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL"

Can't find any reference anywhere which goes against 1.2.0.0 in any of my projects.

Any ideas how I should go about solving this?

Hickie

Could any of your referenced assemblies be using some stuff in old Unity library? – Siberson

Probably... but how can I find which assemblies? I have a lot of projects in my solution and a lot of potential suspects... trial and error bruteforce seems a bit hopeless... – Hickie

You only have to look into the referenced assemblies in the project for which you get this error. – Siberson

It's not the assembly reference, you reference version 2.0. But at runtime, the CLR is finding 1.2, an old version. If you don't see that old DLL in your build directory then use Fuslogvw.exe to find out how the CLR found this old copy. – Todhunter

Look at your project's bin folder and see if your project's dll has a conflict in it's name. Just delete that one and then Rebuild your solution. That worked for me. – Farris

Possible duplicate of Could not load file or assembly 'Microsoft.Practices.Unity' – Mochun

"or one of its dependencies" is the part that really annoys me. If it can't load "one of its dependencies" the error should say which "one of its dependencies" can't be loaded. The current form is useless, it might as well say can't load thinggy – Keratin

Answer 1

1. Check if you are referencing an assembly which in turn referencing an old version of unity. For example let's say you have an assembly called ServiceLocator.dll which needs an old version of Unity assembly, now when you reference the ServiceLocator you should provide it with the old version of Unity, and that makes the problem.

2. May be the output folder where all projects build their assemblies, has an old version of unity.

You can use FusLogVw to find out who is loading the old assemblies, just define a path for the log, and run your solution, then check (in FusLogvw) the first line where the Unity assembly is loaded, double click it and see the calling assembly, and here you go.

Gelderland

Where's the log file of FuseLogVw – Preventer

To avoid having to find the log file, you can specify a custom log path: Settings, check the Enable custom log path checkbox, enter a custom log path, refresh. – Greybeard

Other tips: 1) Run the tool as admin 2) Go to the tool's settings and make sure that you have chosen "Log bind failures to disk" 3) You ~may~ need to restart IIS Admin Service to see the desired output – Bolme

Answer 2

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.

Varnish

IIS -> select each ApplicationPool -> Basic Settings -> check if the latest framework is selected under the ".NET Framework version" dropdown – Recognizee

You can also right click your project in VS . and remove the prefer 32 bit checkmark – Eva

Thanks. It worked. Well it was already True in my case , just for try. I made it False and it worked. – Ellery

When I merged a project from 1 server to another, this flag was indeed False again, thanks for the solution! – Magnolia

Answer 3

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.

Churchy

Yeah, same here, combined with doing a Clean Solution. After I did that, VS highlighted a build error that wasn't showing up before. Previously it said Rebuild All Succeeded after rebuilding - I was referencing the wrong namespace for a class. – Bona

Answer 4

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

Brassy

This issue can be caused by a lot of things ... your solution solved my problems, and might solve others' as well. – Cline

@ScottRippey This worked for me to. I first deleted all .pdb files and then reloaded my project and rebuild it. – Sharkskin

Worked for me, I just deleted the bin/ folder and built the solution again. – Sepaloid

And still in 2023 this fairly annoying issue is present in VS2022. Thank you for this solution! – Marabelle

Answer 5

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: https://marketplace.visualstudio.com/vsgallery/051172f3-4b30-4bbc-8da6-d55f70402734

Example of output:

Cero

Does not work with Community editions of Visual Studio – Kerrykersey

I believe there should be another issue, not related to Visual Studio edition. I tested the extension on VS 2017 and VS 2015 Community editions. Actually it was developed by means of VS 2017 Community edition. – Cero

Aha. Do you have any other extensions installed? This page says that DGML is not supported in VS Community: msdn.microsoft.com/en-us/library/hh871439.aspx#VersionSupport – Kerrykersey

There are no architecture tools in the Community edition but the DGML editor itself it available. You can install it selecting "Install DGML editor" under "Individual Components" -> "Code Tools" via Visual Studio Installer -> Modify – Cero

Answer 6

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

Lipetsk

Dependency walker is great, but copying random DLLs from the internet to Windows is ... less great. It's better to try to find the installer that provides those dlls. – Joubert

I got a few files (API-MS-WIN-CORE-KERNEL32-PRIVATE-L1-1-1.DLL) not found and led me to this stackoverflow question. Basically keep in mind could be looking at false positive for some files, link provides more detail. – Inchmeal

This may solve my problem, but MalwareBytes is warning me from using the site. – Lord

Answer 7

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.

Charlenecharleroi

Answer 8

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)

Killian

Answer 9

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

Isochroous

After checking application pool, "Enable 32-Bit Applications" was set to False, but my platform target was x86. Changing it to Any CPU OR x64 fixed my issue. – Endres

Answer 10

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.

Palstave

This worked for me although it was web.config, not app.config – Constantine

Answer 11

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?

Theodoratheodore

Answer 12

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.

Scraggy

Answer 13

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 ...

Dania

Answer 14

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.

Tarah

Excellent! My dll file name and the namespace were different, I copied the namespace and renamed my dll. – Wilk

Answer 15

• 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).

Profanity

I dont have "Solution -> Package" in my VS2010 project – Gonadotropin

Answer 16

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.

Arneson

Answer 17

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)

Incuse

Spent so long on this and I cannot believe this was the answer. It's usually good go-to solution when you're seeing some odd behavior within VS. Thank you. – Weatherbeaten

Answer 18

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

I had to change from MIXED PLATFORMS to ANY CPU.

Thundershower

Answer 19

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.

Kremlin

Answer 20

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

Italianism

Answer 21

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

Asp

Answer 22

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".

Shopping

#517230 – Tetraploid

Answer 23

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.

Drive

Answer 24

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.

Benoite

Answer 25

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.

Jaenicke

Answer 26

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

Indiscerptible

This took me hours to figure out.... I accidentally named my unit test project the same name as the main project, so the unit test project dll must have been overwriting the project dll – Khalsa

Answer 27

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

Microsoft.Practices.Unity.Interception.dll

Interior

Answer 28

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).

Warnock

Answer 29

For me rebuilding the unity game without Unity C# Projects Checkmark worked.

Geber

Answer 30

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.

Adultery

Answer 31

Try checking if the "Copy to Local" property for the reference is set to true and the specific version is set to true. This is relevant for applications in Visual Studio.

Shotgun

Answer 32

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.

Overstrung

I only needed to delete the obj folder and compile again – Supper

Answer 33

Okay this may sound very stupid, but heres how I solved the issue after trying out every other solution and spending a night on this stupid thing.

I was getting the same error with some DLL missing from Bin Folder. I tried to delete , get back up everything from Team Foundation Server but didn't work. Got a copy of Bin folder from my office-matelocal machine, and replaced it. It didn't work either. At last, I manually FTPed server, got the copy of DLL which was showing up as missing, and then it started showing up that next file in the file list sequence is missing.

So I ftped server Got all Bin Folder, Manually replaced each file one by one. (Not Ctrl + All and replace.. I tried : it didn't work.) And somehow it worked...

Arbitrate

Answer 34

My solution was:

I have a three-tier application and I forgot to copy the DLL also to the right path at IIS. Just after copied it to the right place it worked for me.

Circumjacent

Answer 35

I kept getting this error on my web forms project in visual studio 2015. I shutdown Visual Studio and I killed the ScriptedSandbox64.exe, Microsoft.VsHub.Server.HttpHostx64.exe, Microsoft.VsHub.Server.HttpHostx.exe *32, Microsoft.VisualStudio.Web.Host.exe *32 processes and it seemed to help fix the issue.

Dissimilate

Answer 36

I wasted a few frustrating hours on this problem too. We had to update our version of the .NET Framework, and started getting multiple “Could not load file or assembly or one of its dependencies” for several DLLs that had not been changed for years. Strangely, the versions being searched for in the error messages were all extremely old. For example, it was searching for Newtonsoft.Json version 6.0.0 while we had been using 8.0.1 for years.

Reverting to these ancient versions was not an option, and anyway there were a bunch of bindingRedirect elements in our web.config file that were supposed to redirect calls to old DLLs to the new ones. Rolling back the .NET version made the errors go away, but we needed the new version. What is going on?

The <runtime> element in our web.config file contained the element:

<assemblyBinding appliesTo="v2.0.50727"
    xmlns="urn:schemas-microsoft-com:asm.v1">

The dependentAssembly elements that seemed to be ignored were contained in that.

The culprit was the appliesTo attribute. It meant the bindingRedirect applies only to .NET version 2.0.50727. When we updated the .NET Framework version, all our bindingRedirect elements were ignored.

The solution in our case was to remove the appliesTo attribute entirely.

Lamdin

Answer 37

I do the following to work out which dependency cannot be found.

Run regedit.exe and navigate to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Fusion

Create the following:

LogFailures set value to 1 (DWORD)
LogResourceBinds set value to 1 (DWORD)
LogPath (String) set value to C:\FusionLog\

Now run your program and wait for it to raise Could not load file or assembly or one of its dependencies.

Using explorer, navigate to C:\FusionLog and there should be a folder containing logs for your program, showing which dependency is missing.

Note: Some people use FUSLOGVW.exe, which is a viewer for these Fusion Logs. On my machine it can be found in multiple places, including:

C:\Program Files (x86)\Microsoft SDKs\Windows\v10.0A\bin\NETFX 4.7.2 Tools\x64\FUSLOGVW.exe

Jalopy

Answer 38

I had this problem, the mistake was actually very silly. I had specified the wrong location for the .dll file, after changing the location to correct location the loading happened correctly (answering so someone else don't make this mistake).

Handicapper

Answer 39

For me, it seems that Nuget wasn't playing nice with my project/solution. I used Nuget to install NewtonSoft.Json The project file seemed to reference it correctly, and when I R-clicked the dll name in Solution Explorer/Dependencies/Nuget, then clicked Properties, I found that the dll existed where properties said it should be.

I deleted the Nuget package and did R-click Project > Add > Reference and browsed to the dll in a packages directory when a former Nuget process had installed it, and then the Solution ran fine.

NOTES: this solution is quite a a hodge podge, starting with a Xamarin.iOS solution and adding a .netstandard project (which is where I had difficulty using Nuget). There is also a "portable" project in the solution. I inherited all this from a dev who has been gone for 3 years. Ha ha.

Epithelioma

Answer 40

I have a C# Winforms project called SetTags with a large number of forms that I use Visual Studio 2013 to work on. After editing one of them and trying to build I got the error:

Could not load file or assembly 'SetTags Version = 2.1.85.0, Culture=neutral,PublicKeyToken=null' or one of its dependencies. The system cannot find the file specified.

The error also appeared when I tried to save the project or to close the form I had been working on.

I fixed the problem by removing a recently added radio button control and commenting out all references to it, then added the control again and uncommenting the code. This allowed me to save the form, and on closing restarting VS the problem had disappeared.

My Visual Studio environment has many occasional problems - Toolbox not showing or appearing only on VS startup, unrecognized custom controls when trying to view a form in Design mode - and it may be that I need to move on to a later VS version.

Mashie

Answer 41

A strange fix for me, but I had just pulled this solution from source control.

Was getting this error, went through most of the answers above, and then deleted the solution and re-pulled the solution from source control.

Worked.

Will only apply to a few, but I guess I was one of the few so there will be more. Not sure what happened the first time, but somehow some assemblies must have had some issues when I pulled them across.

Essentially turn it off and on again.

Mcburney

Answer 42

Your project's csproj file must contain a package reference of Microsoft.Practices.Unity and this could not be found in the global-packages folder (%userprofile%.nuget\packages), running dotnet restore fixes the issue

Mak

Answer 43

Step 1: Remove the Existing Reference Step 2: Clean Solution Step 3: Add project Reference again.

and its done. :)

Pipestone

Answer 44

TLDR; the solution for me was to restore default settings in visual studio.

---

I'm on visual studio 2019 community edition and I had this issue for same dll file across different projects that I didn't touch.

After trying out all the answers in this question (as of 2020-07-22 7:13UTC) I decided to repair visual studio installation (backed up my settings beforehand). After installation opened the solutions that had the problem and the problem was gone. After that imported my settings that and the problem came back!! So without repairing visual studio installation again (which takes a few minutes + one restart) I've simply restored VS default settings and then it works. If I end up having time to investigate, I'll edit the answer and pinpoint the underlaying issue

Armhole

Answer 45

I know this is an old post, but I made a PowerShell module to list dependencies, and which ones failed to load.
You can install it with:

Install-Module LibSnitcher
Import-Module LibSnitcher

To list the complete dependency chain:
(You can use the -Depth parameter to set the recursion depth)

Get-PeDependencyChain -Path C:\Path\To\Your\Module.dll

To list modules that failed to load:

Get-PeFailedDependency -Path C:\Path\To\Your\Module.dll

There is a complete README at the project page, here

Hope it helps, let me know how can I improve it!

Devondevona