Could not load file or assembly 'System.Threading.Tasks.Extensions, Version=4.2.0.0

Question

I recently installed CsvHelper (https://joshclose.github.io/CsvHelper/) when i try to use the library I get the following error:

Could not load file or assembly 'System.Threading.Tasks.Extensions, Version=4.2.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040)

In my app.config I have binding redirect:

 <dependentAssembly>
            <assemblyIdentity name="System.Threading.Tasks.Extensions" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
            <bindingRedirect oldVersion="0.0.0.0-4.2.0.1" newVersion="4.2.0.1" />
        </dependentAssembly>

Also in my project I have reference to

\packages\System.Threading.Tasks.Extensions.4.5.3\lib\netstandard2.0\System.Threading.Tasks.Extensions.dll

Its version is 4.2.0.1 I am not sure why its still trying to load 4.2.0.0 of the library.

my project is running .net 4.7.2

Is this a single project solution, or multi-project? I've noticed in Framework (not Core) that sometimes I need to install all packages and their dependencies into the entry-point project if they are used anywhere in the solution, or I get runtime errors. — JamesFaix
– JamesFaix, Commented Feb 12, 2020 at 18:01
I have 2 projects a console app and the other is test project with nunit. The tests is referencing the console one both are .net 4.7.2 both have references to System.Threading.Tasks.Extensions — Ismail
– Ismail, Commented Feb 12, 2020 at 18:25
Just created new console app .net core 2.2 and that works fine. — Ismail
– Ismail, Commented Feb 12, 2020 at 18:34
I needed to upgrade a different nuget dependency that was requiring an earlier version than what my projects had installed. — Subjective Reality
– Subjective Reality, Commented Jan 27, 2021 at 0:06

StayOnTarget · Accepted Answer · 2022-04-07 19:31:48Z

23

I had the same problem today in a multi project solution, System.Threading.Tasks.Extensions got installed by embedding the Autofac package. After removing and reinstalling Autofac (via nuget) in both projects, the two packages.config contained the same entry

<package id="System.Threading.Tasks.Extensions" version="4.5.4" targetFramework="net472" />

but while one project referenced the correct dll in

packages\System.Threading.Tasks.Extensions.4.5.4\lib

the other one referenced the older version in

packages\System.Threading.Tasks.Extensions.4.5.2\lib

After manually removing the older dll from the references (not via nuget) and embedding the correct one, everything worked again. I don't see why the correct packages.config entry did not enforce the correct reference.

EDIT:

If it works on your dev machine but not on the machine you deployed to, don't forget to deploy the binding redirects in web.config / app.config. In my case they look like so:

<dependentAssembly>
  <assemblyIdentity name="System.Threading.Tasks.Extensions" publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
  <bindingRedirect oldVersion="0.0.0.0-4.2.0.1" newVersion="4.2.0.1" />
</dependentAssembly>

edited Apr 7, 2022 at 19:31

StayOnTarget

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answered May 8, 2020 at 22:19

IngoB

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5 Comments

StayOnTarget Over a year ago

What did you mean by "embedding"?

IngoB Over a year ago

@StayOnTarget: embedding = installing via Nuget.

Majid Shahmohammadi Over a year ago

You saved my week !! :)

canvee Over a year ago

Adding the binding redirect was the solution for me :) Thank you :)

dtwk2 Over a year ago

i also had referenced Autofac, but, for me, the solution was to remove the above binding redirect from my app.config

Furkan Cevdet · Accepted Answer · 2021-10-08 11:38:59Z

10

I had this problem in a multi-project solution when upgrading .net version. In my case running Update-Package -reinstall command in Package Manager Console solved the problem.

answered Oct 8, 2021 at 11:38

Furkan Cevdet

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1 Comment

J.J Over a year ago

I found useful the flag -ProjectName to target only one of my projects instead of the entire solution

StayOnTarget · Accepted Answer · 2024-10-09 15:54:34Z

4

According to https://github.com/JoshClose/CsvHelper/issues/1462 this seems to be a bug in one of the CSVHelper 15.0.0 dependencies. The 15.0.0 version (not sure about earlier ones) brings in some other assembly which causes the problem.

Personally I worked around this by downgrading to 13.0 (a comment also noted that 12.3.2 worked), but that bug report now states that they have released 15.0.1 specifically to fix this. I've yet to confirm that myself.

Edit - years later we have updated to version 19 at some point, and this problem no longer exists.

edited Oct 9, 2024 at 15:54

answered Mar 6, 2020 at 22:23

StayOnTarget

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1 Comment

smirkingman Over a year ago

Installing CSVHelper v19.0.0 fixed this problem for me. Many thanks, would have been a real pain to diagnose.

StayOnTarget · Accepted Answer · 2020-05-13 20:02:06Z

3

So i created a new .NET 472 project then added all the libs etc and code and now it works.

I suspect it originally broke because I had installed a really old version of csvhelper lib with excel plugin. Even though i removed it and removed all references it was still picking it up from somewhere.

edited May 13, 2020 at 20:02

StayOnTarget

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answered Feb 13, 2020 at 7:46

Ismail

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Comments

Tommy Finnegan · Accepted Answer · 2020-09-14 20:24:45Z

2

<assemblyBinding>
  <probing privatePath="System.Threading.Tasks.Extensions.dll"/>
</assemblyBinding>
            <assemblyBinding>
  <probing privatePath="System.Runtime.CompilerServices.Unsafe.dll"/>
</assemblyBinding>
    <assemblyBinding>
  <probing privatePath="Microsoft.Bcl.AsyncInterfaces.dll"/>
</assemblyBinding>

answered Sep 14, 2020 at 20:24

Tommy Finnegan

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2 Comments

Tommy Finnegan Over a year ago

You need to reference the dll files then all will work at runtime

Kiquenet Over a year ago

privatePath is bin\ ? (my app is web NET Framework 4.8)

adamj537 · Accepted Answer · 2020-05-13 20:00:54Z

1

I had this problem today in a multi-project solution. Fixed it by updating other NuGet packages in the offending project. Unfortunately, not sure which one fixed the problem.

Current version of CsvHelper: 15.0.5.

answered May 13, 2020 at 20:00

adamj537

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Comments

Alex Pacheco · Accepted Answer · 2022-12-22 18:45:26Z

1

In my case I had a different version of System.Threading.Tasks.Extensions in my unit testing project than in my main project so after I upgraded my unit testing project to match the version it worked for me.

answered Dec 22, 2022 at 18:45

Alex Pacheco

111 bronze badge

1 Comment

KORIN Over a year ago

This does not provide an answer to the question. Once you have sufficient reputation you will be able to comment on any post; instead, provide answers that don't require clarification from the asker. - From Review

michael hansen079 · Accepted Answer · 2023-09-01 06:53:42Z

1

I go this error when running a console app (.NEt framework 4.7.2) consuming a "native" class library, which in turn consumed the System.Threading.Tasks.Extensions dll. Removing the class library from the console application and then re-adding it again, solved the issue.

answered Sep 1, 2023 at 6:53

michael hansen079

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Comments

Mukesh Piprotar · Accepted Answer · 2024-12-17 12:49:12Z

1

i resolved a issue by updating Microsoft.Bcl.AsyncInterfaces from 1.1.0 to 7.0.0

answered Dec 17, 2024 at 12:49

Mukesh Piprotar

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Comments

Harsh · Accepted Answer · 2022-04-13 06:35:20Z

This answer assumes that you are using PackageReference for your nuget references. If that's the case, there is also a known bug in PackageReference .Net tooling model. For some weird cases, the nuget restore msbuild tool chain places ref assemblies, when it should have ideally placed the lib assemblies. How can you find out if you are facing a similar problem? You can use a standard reflector application like ILSpy to read the failing library's metadata in your working directory. If you see RefAssemblies attribute in its metadata, then you are also encountering this problem.

To fix this problem, you can use something like the following tag in your csproj file to fix the nuget copying issue.

<Target Name="ReplaceRefWithLib" BeforeTargets="ResolveAssemblyReferences">
    <ItemGroup>
        <_noCopyRefs Include="@(Reference)" Condition="'%(Reference.Private)' == 'false'" />
        <_noCopyRefsByFileName Include="@(_noCopyRefs->'%(FileName)')">
            <OriginalItem>%(Identity)</OriginalItem>
        </_noCopyRefsByFileName>
        <_libByFileName Include="@(ReferenceCopyLocalPaths->'%(FileName)')">
            <OriginalItem>%(Identity)</OriginalItem>
        </_libByFileName>
        <_overlappingRefByFileName Include="@(_noCopyRefsByFileName)" Condition="'@(_noCopyRefsByFileName)' == '@(_libByFileName)' AND '%(Identity)' != ''" />
        <_overlappingLibByFileName Include="@(_libByFileName)" Condition="'@(_noCopyRefsByFileName)' == '@(_libByFileName)' AND '%(Identity)' != ''" />
        <_overlappingRef Include="@(_overlappingRefByFileName->'%(OriginalItem)')" />
        <_overlappingLib Include="@(_overlappingLibByFileName->'%(OriginalItem)')" />
    </ItemGroup>
    <ItemGroup Condition="'@(_overlappingRef)' != ''">
        <Reference Remove="@(_overlappingRef)" />
        <Reference Include="@(_overlappingLib)">
        <Private>false</Private>
        </Reference>
    </ItemGroup>
</Target>

Hoping this helps.

StayOnTarget · Accepted Answer · 2024-02-22 20:51:51Z

0

I had similar issue for couple of dlls which added newly in C# project references where I was using .exe.config file to do binding redirect. I have mentioned old and new version in .exe.config file but it was giving same error. I used this link to enable binding redirect logs: How to enable assembly bind failure logging (Fusion) in .NET I found out that sometime dll getting loaded from wrong folder(as at multiple location same dll with different version are available) or wrong binding version given in .exe.config

example: Folder path where .exe.config placed : C:\folder1

Folder path where System.Threading.Tasks.Extensions.dll placed : C:\folder1\abc\xyz

edited Feb 22, 2024 at 20:51

StayOnTarget

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answered Feb 22, 2024 at 15:16

Sachin Aoundhkar

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1 Comment

StayOnTarget Over a year ago

If you can, better to add code as text instead of as an image.

Mykyta Halchenko · Accepted Answer · 2024-05-27 18:27:04Z

0

For those who tried but without result. Try removing the package and adding via NuGet again, for me it helped.

answered May 27, 2024 at 18:27

Mykyta Halchenko

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Comments

bryanbcook · Accepted Answer · 2024-10-09 14:13:29Z

0

Ensure that Web.config has the correct binding redirects for System.Threading.Tasks.Extensions
Add the following binding redirect if it's missing or incorrect:

<configuration>
  <runtime>
    <dependentAssembly>
      <assemblyIdentity name="System.Threading.Tasks.Extensions" 
      publicKeyToken="cc7b13ffcd2ddd51" culture="neutral" />
      <bindingRedirect oldVersion="0.0.0.0-4.2.0.1" newVersion="4.2.0.1" />
    </dependentAssembly>
  </runtime>
</configuration>

After adding this, clean and rebuild your application, and it should run as expected.

edited Oct 9, 2024 at 14:13

bryanbcook

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answered Oct 9, 2024 at 10:50

heartbeat

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