diff --git a/src/Umbraco.Core/UriExtensions.cs b/src/Umbraco.Core/UriExtensions.cs
index 05c5da7450..cddd4ef83f 100644
--- a/src/Umbraco.Core/UriExtensions.cs
+++ b/src/Umbraco.Core/UriExtensions.cs
@@ -46,7 +46,7 @@ namespace Umbraco.Core
             var urlPath = fullUrlPath.TrimStart(appPath).EnsureStartsWith('/');
             
             //check if this is in the umbraco back office
-            var isUmbracoPath = urlPath.InvariantStartsWith(GlobalSettings.Path.EnsureStartsWith('/'));
+            var isUmbracoPath = urlPath.InvariantStartsWith(GlobalSettings.Path.EnsureStartsWith('/').TrimStart(appPath.EnsureStartsWith('/')).EnsureStartsWith('/'));
             //if not, then def not back office
             if (isUmbracoPath == false) return false;