diff --git a/Global_Indexer/frmIndex.vb b/Global_Indexer/frmIndex.vb
index ba395ca..40c0a9a 100644
--- a/Global_Indexer/frmIndex.vb
+++ b/Global_Indexer/frmIndex.vb
@@ -863,11 +863,11 @@ Public Class frmIndex
                                 End If
 
                                 If oOverwrite = False Then
-                                    oListofString = oExistingItems.Concat(oListofString)
+                                    oListofString = oExistingItems.Concat(oListofString).ToList()
                                 End If
 
                                 If oPreventMultipleValues = True Then
-                                    oListofString = oListofString.Distinct()
+                                    oListofString = oListofString.Distinct().ToList()
                                 End If
 
                                 indexierung_erfolgreich = WINDREAM.SetFileIndex(CURRENT_NEWFILENAME, oIndexName, oListofString, CURR_DOKART_OBJECTTYPE)