To determine which dotnet core version you have installed, you can use either of these three methods:
- Check the version:
dotnet --version
-
Check the file location: The dotnet sdk packages are located in
C:\Program Files\dotnet\sdk
-
Get info for all versions installed:
dotnet --info
Note that .NET Core versions are specific to the Visual Studio installation. In my case, I was using Visual Studio 2017 CE that could not be used with .NET Core 3.x. prompting me to install VS 2019.
https://dotnet.microsoft.com/download/visual-studio-sdks
https://dotnet.microsoft.com/download/dotnet-core/thank-you/sdk-3.1.101-windows-x64-installer
-- getting started with Blazor https://docs.microsoft.com/en-us/aspnet/core/blazor/get-started?view=aspnetcore-3.1&tabs=visual-studio