Also check the MSBuild version set in File | Settings | Build, Execution, Deployment | Toolset and Build ( jetbrains://Rider/settings?name=Build%2C+Execution%2C+Deployment--Toolset+and+Build ), for some reason I had to change mine from one in the C:\Program Files\JetBrains\ folder to one in C:\Program Files\dotnet\sdk\ for it to load my project.