An assembly specified in the application dependencies manifest (...) was not found - asp.net-core

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

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.

Answer 3

For me, the marked answer didn't solve the issue. My issue was when trying to Add-Migration
Add-Migration -Name initial-migration -Context Mysln.Data.MyDbContext -StartupProject Mysln -Project Mysln.Core
And the error was like this:
I solved it by downgrading all my Entityframework packages to 2.0.0 instead of the latest 2.2.0-preview one.

Answer 4

If you have more than one project in your solution like me:
and if you want to scaffold dbcontext in your "non startup" project (InstantOrder.Functions.Data in my case)
then you should add the -StartupProject parameter of the Scaffold-DbContext command like this -
Scaffold-DbContext "Server=..." -Project InstantOrder.Functions.Data -StartupProject InstantOrder.Functions.Data

Answer 5

I know this may be old, but just in case it can help some one else, this one worked for me:
Adding:
<CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
To the PropertyGroup in the .csproj file.

Answer 6

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 7

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 8

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 9

I got this error while running Scaffold-DbContext command on the Library project.
Solution:
Remove the Azure Function project from the solution, and then run this command.
After that, use add an existing project feature to add the Azure Function project again in the solution.

Answer 10

The correct .NET Core runtime was not installed on my PC. I had NETCore.App 2.1 and 2.2, but the project was targeted to 2.0.
dotnet --list-runtimes
I installed the correct runtime from the dot.net site and it resolved the issue.

Answer 11

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 12

This happened to me when I published my Lambda to AWS after renaming the project. I deleted both the obj and bin folders, rebuilt, republished and that fixed it.

Answer 13

I changed filters in Yaml.
Had projects called TestHelper etc...
Testrunner tried to run projects without tests, and the build was flagged as failed.
Added:
!**\*Helper*.*
To:
- task: DotNetCoreCLI#2
inputs:
command: 'test'
projects: |
**\*test*.dll
!**\*TestAdapter.dll
!**\obj\**
!**\*TestPlatform*.dll
!**\*Testing*.*
!**\*TestHost*.*
!**\*Helper*.*