An assembly specified in the application dependenc

Question

I upgraded Microsoft.AspNetCore from 2.0.3 to 2.0.5 and my WebAPI project, although running successfully locally, fails to start in production (IIS). Everything was fine in production until this upgrade. The error message produced in the log directory is as follows:

Error:
  An assembly specified in the application dependencies manifest (MyProject.WebAPI.deps.json) was not found:
    package: 'Microsoft.AspNetCore.Mvc.Abstractions', version: '2.0.2'
    path: 'lib/netstandard2.0/Microsoft.AspNetCore.Mvc.Abstractions.dll'

  This assembly was expected to be in the local runtime store as the application was published using the following target manifest files:
    aspnetcore-store-2.0.5.xml

Could someone explain to me the details of exactly what this means? I assume it's a version mismatch of sorts, but why is this occurring? I thought the latest stable releases of NuGet packages weren't supposed to have such issues.

I was able to resolve the issue by downgrading Microsoft.AspNetCore.All from 2.0.5 to 2.0.3, but would like to find a better solution to the issue so I can use the most up-to-date version of this package.

Answer 1

Development machines usually have the SDK installed but on production the runtime only.

Add the following to your .csproj file and publish again.

<PropertyGroup>               
    <PublishWithAspNetCoreTargetManifest>false</PublishWithAspNetCoreTargetManifest>
</PropertyGroup>

Answer 2

To solve the first half of the error message, An assembly specified in the application dependencies manifest (…) was not found be sure to always use the publish output when deploying to a target sever.

For a self-contained application it can be found in

bin\Release\netcoreapp2.0\win81-x64\publish

or for framework-dependent deployments in

bin\Release\netcoreapp2.0\publish

The output in the directories above are meant to be used in development only, since they are specific to machine and user configuration built with.

Taken from a related answer.

Answer 3

2 cents: If you just take from the build folder, the dlls for the dependency aren't provided. If you publish the folder, they are. This was the fix for me.

Answer 4

I had this error however my solution was somewhat different from what was posted above. My problem was that I was deploying via a zip file and while building the zip file I wasn't including sub directories therefore required files were not being included.

So if you are publishing via a zip file make sure to include all sub folders while building the zip.

Answer 5

In most case you get that error because there's misalignment of versions.

I changed the Microsoft.VisualStudio.Web.CodeGeneration.Design version, an it worked.

Before

PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="3.1.0" />

After

PackageReference Include="Microsoft.VisualStudio.Web.CodeGeneration.Design" Version="2.2.4" />

Answer 6

Sometimes this is related to the Startup Project, For example if the migration is a class library in Azure Functions project. You have to make sure when you run Add-Migration while the EF Library project is selected as Startup Project.