Empty VS2019 project (set up as I do all my projects, empty c# web application but with mvc ticked). Used Nuget PM to add Umbraco.cms.

On 1st build I got:

    Server Error in '/' Application.
No factory has been set.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.InvalidOperationException: No factory has been set.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:


[InvalidOperationException: No factory has been set.]
   Umbraco.Core.Composing.Current.get_Factory() in D:\a\1\s\src\Umbraco.Core\Composing\Current.cs:53
   Umbraco.Web.Composing.ModuleInjector`1.Init(HttpApplication context) in D:\a\1\s\src\Umbraco.Web\Composing\ModuleInjector.cs:41
   System.Web.HttpApplication.RegisterEventSubscriptionsWithIIS(IntPtr appContext, HttpContext context, MethodInfo[] handlers) +523
   System.Web.HttpApplication.InitSpecial(HttpApplicationState state, MethodInfo[] handlers, IntPtr appContext, HttpContext context) +176
   System.Web.HttpApplicationFactory.GetSpecialApplicationInstance(IntPtr appContext, HttpContext context) +220
   System.Web.Hosting.PipelineRuntime.InitializeApplication(IntPtr appContext) +303

[HttpException (0x80004005): No factory has been set.]
   System.Web.HttpRuntime.FirstRequestInit(HttpContext context) +659
   System.Web.HttpRuntime.EnsureFirstRequestInit(HttpContext context) +89
   System.Web.HttpRuntime.ProcessRequestNotificationPrivate(IIS7WorkerRequest wr, HttpContext context) +189

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.8.4075.0

After a few ponderings, I downgraded to 8.6.1 (which I have used in the past) and everything ran as expected.