Could not load file or assembly 'System.Runtime, Version 10.0.0.0

[Michael-Surma]

I am trying to set up database first connection to a SqlServer database using: scaffold-dbContext "Server=SQLEXPRESS; Database=TTS1000; Trusted_Connection=True;" Microsoft.EntityFrameworkCore.SqlServer -o Models

Even with a brand new wpf .net8.0 project, I get this error: Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
File name: 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

[mscott161]

I ran into the same issue. If you go back to version 9.0.11 for all the EntityFrameworkCore packages then close and re-open the project/solution it will work.

[roji]

Even with a brand new wpf .net8.0 project [...]

EF 10 does not support .NET 8.0, only .NET 10. I'm not sure exactly what it is that you'er trying to do, but the above doesn't seem related to EF itself in any way.

[kaseidu]

I’m seeing the same problem.

EF Tool: 10.0.0
EF Packages: 9.0.11
Target Framework: .NET 9

Running:
dotnet ef database update

Produces:
Build started... Build succeeded. Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.

---

Works

EF Tool: 9.0.11
EF Packages: 9.0.11
Target Framework: .NET 9

---

Works

EF Tool: 9.0.11
EF Packages: 9.0.11
Target Framework: .NET 8

---

The EF Core tool is supposed to be backward compatible? with older EF Core package versions, so using the 10.0.0 tool with 9.x packages should work.
This failure appears to break that compatibility expectation.

[roji]

@kaseidu and others, what I see above are isolated error messages, with no way for me to actually reproduce them.

Please post a minimal, runnable repro (console program) that shows the error happening, with a clear set of steps. Otherwise we can't investigate this.

[tmb-dk-hostmaster]

I just ran into the same issue. Here is my setup:

Fails

EF Tool: 10.0.0
EF Packages: 9.0.10
Target Framework: .NET 8

Works

EF Tool: 9.0.11
EF Packages: 9.0.10
Target Framework: .NET 8

[roji]

Confirmed based on the above, thanks.

To repro:

• Create a minimal EF console program
• Ensure the EF tools (dotnet-ef) 10.0.0 are installed globally
• Reference EF 9.0.x packages (see csproj below)
• Target net8.0 (see csproj below)
• Execute dotnet ef migrations add initial

This fails with the following:

➜  test git:(ef) ✗ dotnet ef migrations add initial    
Build started...
Build succeeded.
Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.

File name: 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

Installing dotnet-ef 9.0.11 makes the error go away.

@AndriySvyryd you seem to know the most about this kind of stuff so assigning to you, at least for now.

csproj

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
      <OutputType>Exe</OutputType>
      <TargetFramework>net8.0</TargetFramework>
      <LangVersion>latest</LangVersion>
      <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
      <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.5" />
      <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.5" />
      <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.5" />
  </ItemGroup>

</Project>

Minimal console program (unimportant)

await using var context = new BlogContext();

public class BlogContext : DbContext
{
    public DbSet<Blog> Blogs { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        => optionsBuilder
            .UseSqlServer("Server=localhost;Database=test;User=SA;Password=Abcd5678;Connect Timeout=60;ConnectRetryCount=0;Encrypt=false")
            .LogTo(Console.WriteLine, LogLevel.Information)
            .EnableSensitiveDataLogging();
}

public class Blog
{
    public int Id { get; set; }
    public required string Name { get; set; }
}

[Michael-Surma]

Resolved. Yes, The EntityFramework packages that I should have used were 8.x. From: Shay Rojansky ***@***.***> Sent: Wednesday, November 19, 2025 10:19 AM To: dotnet/efcore ***@***.***> Cc: Michael Surma ***@***.***>; Author ***@***.***> Subject: Re: [dotnet/efcore] Could not load file or assembly 'System.Runtime, Version 10.0.0.0 (Issue #37201) You don't often get email from ***@***.******@***.***>. Learn why this is important<https://aka.ms/LearnAboutSenderIdentification> [https://avatars.githubusercontent.com/u/1862641?s=20&v=4]roji left a comment (dotnet/efcore#37201)<#37201 (comment)> Confirmed based on the above, thanks. To repro: * Create a minimal EF console program * Ensure the EF tools (dotnet-ef) 10.0.0 are installed globally * Reference EF 9.0.x packages (see csproj below) * Target net8.0 (see csproj below) * Execute dotnet ef migrations add initial This fails with the following: ➜ test git:(ef) ✗ dotnet ef migrations add initial Build started... Build succeeded. Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified. File name: 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' Installing dotnet-ef 9.0.11 makes the error go away. @AndriySvyryd<https://github.com/AndriySvyryd> you seem to know the most about this kind of stuff so assigning to you, at least for now. csproj <Project Sdk="Microsoft.NET.Sdk"> <PropertyGroup> <OutputType>Exe</OutputType> <TargetFramework>net8.0</TargetFramework> <LangVersion>latest</LangVersion> <Nullable>enable</Nullable> </PropertyGroup> <ItemGroup> <PackageReference Include="Microsoft.Extensions.Logging.Console" Version="9.0.5" /> <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.5" /> <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.5" /> </ItemGroup> </Project> Minimal console program (unimportant) await using var context = new BlogContext(); public class BlogContext : DbContext { public DbSet<Blog> Blogs { get; set; } protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) => optionsBuilder .UseSqlServer("Server=localhost;Database=test;User=SA;Password=Abcd5678;Connect Timeout=60;ConnectRetryCount=0;Encrypt=false") .LogTo(Console.WriteLine, LogLevel.Information) .EnableSensitiveDataLogging(); } public class Blog { public int Id { get; set; } public required string Name { get; set; } } — Reply to this email directly, view it on GitHub<#37201 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/BDGOBGKPWGSKLUG4FWGQ5ID35SJ6RAVCNFSM6AAAAACMO2PTS2VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZTKNJTGU3TQOJQHE>. You are receiving this because you authored the thread.Message ID: ***@***.******@***.***>>

[dsteinweg]

I am also encountering this, but on a project that targets .NET 9 instead of .NET 8. And it occurs even when using the 9.0.11 version of the EF Core packages.

Doesn't Work

EF Tool: 10.0.0
EF Packages: 9.0.11
Target Framework: .NET 9

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net9.0</TargetFramework>
    <ImplicitUsings>enable</ImplicitUsings>
    <Nullable>enable</Nullable>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.11">
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
      <PrivateAssets>all</PrivateAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.11" />
  </ItemGroup>

</Project>

// See https://aka.ms/new-console-template for more information
Console.WriteLine("Hello, World!");

C:\temp> dotnet tool list dotnet-ef --global
Package Id      Version      Commands
--------------------------------------
dotnet-ef       10.0.0       dotnet-ef

C:\temp> dotnet ef migrations add initial
Build started...
Build succeeded.
Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
File name: 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

[yerald-mora]

Confirmed based on the above, thanks.

To repro:

• Create a minimal EF console program
• Ensure the EF tools (dotnet-ef) 10.0.0 are installed globally
• Reference EF 9.0.x packages (see csproj below)
• Target net8.0 (see csproj below)
• Execute dotnet ef migrations add initial

This fails with the following:

➜ test git:(ef) ✗ dotnet ef migrations add initial
Build started...
Build succeeded.
Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.

File name: 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'
Installing dotnet-ef 9.0.11 makes the error go away.

@AndriySvyryd you seem to know the most about this kind of stuff so assigning to you, at least for now.

csproj

Exe net8.0 latest enable Minimal console program (unimportant)

"Installing dotnet-ef 9.0.11 makes the error go away." => For sake of clarity, this is the workaround, right? but basically, for now we are not able to use dotnet-ef 10 in any other project that is not targeting net 10 correct? i have my pipelines configured in azure with a task to create a migration bundle, but since i'm using the following task

- task: DotNetCoreCLI@2
  displayName: Install EF CLI
  inputs:
    command: 'custom'
    custom: 'tool'
    arguments: 'update --global dotnet-ef'

To always keep my tool updated (due any bugfix or other improvements), now all my pipelines are dying with the same exact exception

Unhandled exception. System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'. The system cannot find the file specified.
File name: 'System.Runtime, Version=10.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

my csproj

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
   /*****/
    <ItemGroup>
    <PackageReference Include="Microsoft.EntityFrameworkCore.Design" Version="9.0.11" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.InMemory" Version="9.0.11" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.SqlServer" Version="9.0.11" />
    <PackageReference Include="Microsoft.EntityFrameworkCore.Tools" Version="9.0.11">
      <PrivateAssets>all</PrivateAssets>
      <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
    </PackageReference>
    <PackageReference Include="Microsoft.Extensions.Configuration.FileExtensions" Version="9.0.0" />
    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="9.0.0" />
  </ItemGroup>
  <ItemGroup>
    <Folder Include="Migrations\" />
  </ItemGroup>
</Project>

Will this be addressed in some fashion? currently i only can think in 2 options

• Upgrade ALL my projects to net 10
• Update ALL my pipelines to use a fixed version of dotnet-ef

Neither option sounds good :(