diff --git a/ATxCommon/Serializables/ServiceConfig.cs b/ATxCommon/Serializables/ServiceConfig.cs
index 03e1adeb8af39d4c97c1f67c018310e69e4f1811..bf65c98526a80ab9030fc7b83f13def00ee4b217 100644
--- a/ATxCommon/Serializables/ServiceConfig.cs
+++ b/ATxCommon/Serializables/ServiceConfig.cs
@@ -403,6 +403,11 @@ namespace ATxCommon.Serializables
             if (!Directory.Exists(c.DestinationDirectory))
                 errmsg += $"can't find (or reach) destination: {c.DestinationDirectory}\n";
 
+            // TmpTransferDir
+            var tmpTransferPath = Path.Combine(c.DestinationDirectory, c.TmpTransferDir);
+            if (!Directory.Exists(tmpTransferPath))
+                errmsg += $"can't find (or reach) temporary transfer dir: {tmpTransferPath}\n";
+
 
             ////////// OPTIONAL PARAMETERS SETTINGS VALIDATION //////////