Visual Basic WPF .NET Framework 48 SDK style project fails to compile: assembly mscorlib not found

[AchimStuy]

Describe the bug

I want to create a legacy .NET Framework 4.8 WPF app in Visual Basic as SDK style project. For C# I can just create a .NET WPF project and change the target framework to net48. Doing the same with Visual Basic results in the error below.

To Reproduce

In Visual Studio:

• create a Visual Basic .NET 6 WPF project
• change TargetFramework to net48
• build

Exceptions (if any)

1>Target MarkupCompilePass1:
1>  C:\Program Files\dotnet\sdk\7.0.102\Sdks\Microsoft.NET.Sdk.WindowsDesktop\targets\Microsoft.WinFX.targets(211,9): error MC1000: Unknown build error, 'Could not find assembly 'mscorlib, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null'. Either explicitly load this assembly using a method such as LoadFromAssemblyPath() or use a MetadataAssemblyResolver that returns a valid assembly.'
1>Done building target "MarkupCompilePass1" in project "WpfApp1.vbproj" -- FAILED.

Further technical details

Microsoft Visual Studio Professional 2022
Version 17.4.4
VisualStudio.17.Release/17.4.4+33213.308
Microsoft .NET Framework
Version 4.8.04084

Installed Version: Professional

Visual Basic Tools 4.4.0-6.22608.27+af1e46ad38d900023f8b1a2839484e471ece1502
Visual Basic components used in the IDE. Depending on your project type and settings, a different version of the compiler may be used.

[mirodyn]

I am having same issue. There seems to be no workaround. I am forced to keep my old WPF VB projects in old .vbproj format. C# works fine.

[adegeo]

@dotnet/wpf-developers

[harry-dickson]

I just collided with this issue. Disappointing.

[L-Jie]

I am having same issue.

[adegeo]

Confirmed: VS 2026 + .NET 10 Project swapped to net48 as the target framework.

I decide to just add a reference to it in the project, and this worked for me:

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

  <PropertyGroup>
    <OutputType>WinExe</OutputType>
    <TargetFramework>net48</TargetFramework>
    <RootNamespace>WpfApp1vb</RootNamespace>
    <UseWPF>true</UseWPF>
  </PropertyGroup>

  <ItemGroup>
    <Reference Include="mscorlib" />
  </ItemGroup>

</Project>

[marcpopMSFT]

Old issue triage: this seems like more of a WPF specific issue so routing there.