The dialog above and the installation of the file is part of LibMan, which provides a lot of functionality for managing client-side libraries. I change the target location to match where Bootstrap was installed by the template by default, but that isn’t required. Your version number may be higher than the one shown in the screenshot below. In this case, we are looking for twitter-bootstrap. The dialog that shows will allow you to search for client-side libraries to include in your application.

Now open the project in Visual Studio and right-click on the project file and select Add > Client-Side Library.

The first step I took was to delete the existing Bootstrap related file which can be found in the wwwroot/lib directory and delete the whole bootstrap directory.

dotnet new webapp -f netcoreapp2.1 Upgrade Bootstrap Files In case you want a project with Bootstrap 3 installed to play around with before attempting a production site the following command, run in a command prompt, will create an ASP.NET Core 2.1 application that has Bootstrap 3.

Visual studio 2019 bootstrap