diff --git a/LiamWorkflowDiagnostics/MainWindow.xaml.cs b/LiamWorkflowDiagnostics/MainWindow.xaml.cs
index bb0a90a..b29ee17 100644
--- a/LiamWorkflowDiagnostics/MainWindow.xaml.cs
+++ b/LiamWorkflowDiagnostics/MainWindow.xaml.cs
@@ -591,14 +591,18 @@ namespace LiamWorkflowDiagnostics
                 }
                 if (string.IsNullOrWhiteSpace(parentPath))
                     throw new InvalidOperationException("Parent Folder Path konnte nicht ermittelt werden.");
+                var ownerSids = ParseIdentifierList(NtfsCreateOwnerSidsTextBox.Text, "Owner SIDs");
+                if (ownerSids.Count == 0)
+                    throw new InvalidOperationException("Owner SIDs: mindestens ein Eintrag ist fuer die Ordneranlage erforderlich.");
 
-                var result = await provider.CreateDataAreaAsync(
+                var result = EnsureSuccessfulResultToken(await provider.CreateDataAreaAsync(
                     folderPath,
                     parentPath,
                     ParseKeyValueLines(CustomTagsTextBox.Text, "Custom Tags"),
-                    ParseIdentifierList(NtfsCreateOwnerSidsTextBox.Text, "Owner SIDs"),
+                    ownerSids,
                     ParseIdentifierList(NtfsCreateReaderSidsTextBox.Text, "Reader SIDs"),
-                    ParseIdentifierList(NtfsCreateWriterSidsTextBox.Text, "Writer SIDs"));
+                    ParseIdentifierList(NtfsCreateWriterSidsTextBox.Text, "Writer SIDs")),
+                    "NTFS Folder Create");
 
                 return MapResultToken(result);
             });
@@ -618,7 +622,7 @@ namespace LiamWorkflowDiagnostics
                     ParseIdentifierList(NtfsEnsureWriterSidsTextBox.Text, "Writer SIDs"),
                     NtfsEnsureTraverseCheckBox.IsChecked ?? false);
 
-                return MapResultToken(result);
+                return MapResultToken(EnsureSuccessfulResultToken(result, "NTFS Ensure Groups / ACLs"));
             });
         }
 
@@ -910,6 +914,22 @@ namespace LiamWorkflowDiagnostics
             };
         }
 
+        private ResultToken EnsureSuccessfulResultToken(ResultToken token, string actionName)
+        {
+            if (token == null)
+                throw new InvalidOperationException($"{actionName}: kein Ergebnis vom Provider erhalten.");
+
+            if (token.resultErrorId != 0)
+            {
+                var message = string.IsNullOrWhiteSpace(token.resultMessage)
+                    ? "Unbekannter Fehler im Provider."
+                    : token.resultMessage.Trim();
+                throw new InvalidOperationException($"[{token.resultErrorId}] {message}");
+            }
+
+            return token;
+        }
+
         private List<object> MapSecurityGroupResults(IEnumerable<Tuple<string, string, string, string>> groups)
         {
             return (groups ?? Enumerable.Empty<Tuple<string, string, string, string>>())