Fixes #U4-1467

src/Umbraco.Core/IO/PhysicalFileSystem.cs

@@ -17,8 +17,8 @@ namespace Umbraco.Core.IO
 
         public PhysicalFileSystem(string virtualRoot)
         {
-            _rootPath = System.Web.Hosting.HostingEnvironment.MapPath(virtualRoot);
-            _rootUrl = VirtualPathUtility.ToAbsolute(virtualRoot);
+            _rootPath = IOHelper.MapPath(virtualRoot);
+			_rootUrl = IOHelper.ResolveUrl(virtualRoot);
         }
 
         public PhysicalFileSystem(string rootPath, string rootUrl)

src/Umbraco.Tests/IO/IOHelperTest.cs

@@ -13,6 +13,13 @@ namespace Umbraco.Tests.IO
     public class IOHelperTest
     {
 
+		[Test]
+		public void IOHelper_ResolveUrl()
+		{
+			var result = IOHelper.ResolveUrl("~/Scripts");
+			Assert.AreEqual("/Scripts", result);
+		}
+
         /// <summary>
         ///A test for MapPath verifying that HttpContext method (which includes vdirs) matches non-HttpContext method
         ///</summary>