Could not load file or assembly Microsoft.Extensions.DependencyInjection.Abstractions, Version=5.0.0.0

[hkzenetex]

In my azure function app project, I receive an assembly not found runtime error Microsoft.Extensions.DependencyInjection.Abstractions, Version=5.0.0.0. However, the assembly is included in multiple packages I installed from NuGet.

Visual Studio: 2019
Target Framework: netcoreapp3.1
Azure Functions Version: v3

Installed packages containing Microsoft.Extensions.DependencyInjection.Abstractions (5.0.0):
Microsoft.Extensions.Http (5.0.0)
Microsoft.Extensions.Logging (5.0.0)
Microsoft.Extensions.Logging.EventSource (5.0.0)

Error:
A host error has occurred during startup operation...
Could not load file or assembly 'Microsoft.Extensions.DependencyInjection.Abstractions, Version=5.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'. The system cannot find the file specified.

Ineffective fix attempts:
Installed Microsoft.Extensions.DependencyInjection.Abstractions (5.0.0) from Nuget, but error persists.

Following a similar issue, #2931, and StackOverflow question, I added to the project file the following.

<PropertyGroup> <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects> <GenerateBindingRedirectsOutputType>true</GenerateBindingRedirectsOutputType> </PropertyGroup>

I also followed an article suggestion. After installing Microsoft.Azure.Functions.Extensions, the error persists.

I also followed another suggestion, and I added the following to my project file. However, the error persists.

<runtime> <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1"> <dependentAssembly> <assemblyIdentity name="Microsoft.Extensions.DependencyInjection.Abstractions" publicKeyToken="adb9793829ddae60" culture="neutral" /> <bindingRedirect oldVersion="5.0.0.0" newVersion="5.0.0" /> </dependentAssembly> </assemblyBinding> </runtime>

20201120
I attempted the workaround suggested in issue #401 of ASP.NET Core Announcements: reference the package for the assembly which is failing to load explicitly in my application. However, the error remains.

Using ILSpy, I found Microsoft.Azure.Functions.Extensions, which I installed from NuGet, references Microsoft.Extensions.DependencyInjection.Abstractions, Version 2.1.0.0.

20201123
I found a related StackOverflow question, which links to issue Azure/azure-functions-vs-build-sdk #472 and finally to issue Azure/azure-functions-host #6893. @AartBluestoke summarized: "this can only be solved by upgrading azure functions to a newer version which has a dependency on the 5.x line of the abstractions."

[olakusibe]

I am having similar issues, ihave explored same possible solutions and I am still stucked.

it seems Microsoft.Extension.Http and Microsoft.EntityframeworkCore Nuget are the problems, once removed the function app works

[BrennanConroy]

Dupe of Azure/azure-functions-host#6893

TLDR; The functions host runs on ~3.1 and will host your app in-process dynamically. What this means is that if the functions host uses 3.1 of DependencyInjection.Abstractions, it will not be able to load 5.0 of the dll in-process for your app, and your app will fail to run.

[ghost]

This issue has been resolved and has not had any activity for 1 day. It will be closed for housekeeping purposes.

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[hkzenetex]

To run my Azure Function project locally, I resolved missing assembly Microsoft.Extensions.DependencyInjection.Abstractions, Version=5.0.0.0 runtime error by referencing the old versions of all its dependent DLLs and by including multiple old versions of this assembly. However, I received errors from GitHub Workflow CI/CD when attempting deployment to Azure.

NU1605: Detected package downgrade

To deploy my Azure Function App, I resolved the NU1605 errors by including in the project file old versions of packages dependent on a common version of the original missing assembly, Microsoft.Extensions.DependencyInjection.Abstractions, and I specifically included the common older versions, 3.1.7 and 3.1.2.

<ItemGroup>
<!--<PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="5.0.0" />-->
<!--<PackageReference Include="Microsoft.Extensions.Http" Version="5.0.0" />-->
<!--<PackageReference Include="Microsoft.Extensions.Logging" Version="5.0.0" />-->
<!--<PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="5.0.0" />-->
<!--<PackageReference Include="Microsoft.Extensions.Logging.EventSource" Version="5.0.0" />-->
<!--<PackageReference Include="Microsoft.Extensions.Options" Version="5.0.0" />-->
<!--<PackageReference Include="Microsoft.Extensions.Options.DataAnnotations" Version="5.0.0" />-->	  
  <PackageReference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="3.1.7" />
  <PackageReference Include="Microsoft.Extensions.Http" Version="3.1.2" />	  
  <PackageReference Include="Microsoft.Extensions.Logging" Version="3.1.7" />
  <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="3.1.7" />
  <PackageReference Include="Microsoft.Extensions.Logging.EventSource" Version="3.1.7" />
  <PackageReference Include="Microsoft.Extensions.Options" Version="3.1.7" /> 	  
  <PackageReference Include="Microsoft.Extensions.Options.DataAnnotations" Version="3.1.2" /> 
</ItemGroup>
<ItemGroup>
  <Reference Include="Microsoft.Extensions.DependencyInjection.Abstractions" Version="3.1.2">    
     <HintPath>..\..\..\..\.nuget\packages\microsoft.extensions.dependencyinjection.abstractions
          \3.1.2\lib\netstandard2.0\Microsoft.Extensions.DependencyInjection.Abstractions.dll</HintPath>
  </Reference>
</ItemGroup>