Introduced GetRequiredUmbracoContext extension on IUmbracoContextAccessor

src/Umbraco.Core/UmbracoContextAccessorExtensions.cs

@@ -0,0 +1,19 @@
+using System;
+using Umbraco.Web;
+
+namespace Umbraco.Core
+{
+    public static class UmbracoContextAccessorExtensions
+    {
+        public static IUmbracoContext GetRequiredUmbracoContext(this IUmbracoContextAccessor umbracoContextAccessor)
+        {
+            if (umbracoContextAccessor == null) throw new ArgumentNullException(nameof(umbracoContextAccessor));
+
+            var umbracoContext = umbracoContextAccessor.UmbracoContext;
+
+            if(umbracoContext is null) throw new InvalidOperationException("UmbracoContext is null");
+
+            return umbracoContext;
+        }
+    }
+}

src/Umbraco.Infrastructure/Intall/InstallSteps/ConfigureMachineKey.cs

@@ -32,8 +32,6 @@ namespace Umbraco.Web.Install.InstallSteps
         private bool HasMachineKey()
         {
             return _machineKeyConfig.HasMachineKey;
-            // var section = (MachineKeySection) WebConfigurationManager.GetSection("system.web/machineKey");
-            // return section.ElementInformation.Source != null;
         }
 
         /// <summary>

src/Umbraco.Infrastructure/Intall/InstallSteps/SetUmbracoVersionStep.cs

@@ -25,7 +25,7 @@ namespace Umbraco.Web.Install.InstallSteps
 
         public override Task<InstallSetupResult> ExecuteAsync(object model)
         {
-            var security = _umbracoContextAccessor.UmbracoContext.Security;
+            var security = _umbracoContextAccessor.GetRequiredUmbracoContext().Security;
             if (security.IsAuthenticated() == false && _globalSettings.ConfigurationStatus.IsNullOrWhiteSpace())
             {
                 security.PerformLogin(-1);

src/Umbraco.Web/HttpContextAccessorExtensions.cs

@@ -7,6 +7,7 @@ namespace Umbraco.Web
     {
         public static HttpContextBase GetRequiredHttpContext(this IHttpContextAccessor httpContextAccessor)
         {
+            if (httpContextAccessor == null) throw new ArgumentNullException(nameof(httpContextAccessor));
             var httpContext = httpContextAccessor.HttpContext;
 
             if(httpContext is null) throw new InvalidOperationException("HttpContext is null");