Getting an "The framework 'Microsoft.NETCore.App', version '3.1.0' (x64) was not found." when running ef migrations on a net6 project

Question

When I try to build the app in Azure Devops I keep encountering the error

The framework 'Microsoft.NETCore.App', version '3.1.0' (x64) was not found. 

when performing ef migrations even though it is fully net6 (nuget package for ef core is 6.0 as well).

There is an agent however that has been polluted with an dotnet 3.1 sdk which generates the following message:

The Entity Framework tools version '3.1.0' is older than that of the runtime '6.0.5'. Update the tools for the latest features and bug fixes. See https://aka.ms/AAc1fbw for more information.

which is strange as I install the ef tools before running the command with the following dotnet-tools.json

{
  "version": 1,
  "isRoot": true,
  "tools": {
    "dotnet-ef": {
      "version": "6.0.6",
      "commands": [
        "dotnet-ef"
      ]
    }
  }
}

Answer 1

Please check if the below steps help to fix the issue:

The Entity Framework tools version '3.1.0' is older than that of the runtime '6.0.5'. Update the tools for the latest features and bug fixes. See https://aka.ms/AAc1fbw for more information.

This error clearly stating to update the entity framework tools version from 3.1.0 to 6.0.5, you can use the below command to update it:

dotnet tool update --global dotnet-ef --version 6.0.5

OR you can also use the latest version command without versioning like:

dotnet tool update --global dotnet-ef

The framework 'Microsoft.NETCore.App', version '3.1.0' (x64) was not found.

Normally, to build the .NET 5 Application, .NET Core 3 SDK is required and installed alongside with the 5.0 version.

It might be your project has dependencies with the .NET Core 3 so get it installed and check once.