I had to search for it, it's not very intuitive. The core issue is the difference between the way .csproj and .fsproj are handled. For C#, there's a lot of stuff done automagically, which is not the case for F#. In your .fsproj, you need to use an element `FrameworkReference` with the name of the library, since those libraries are part of the framework. ><PropertyGroup> →→… →→<UseWpf>true</UseWpf> </PropertyGroup> … <ItemGroup> →→<FrameworkReference Include="Microsoft.WindowsDesktop.App.WPF" /> </ItemGroup> Keywords: fsharp netcore 3.1