diff --git a/lib/core/option.py b/lib/core/option.py
index 7034fc671..fa661dfb2 100644
--- a/lib/core/option.py
+++ b/lib/core/option.py
@@ -1361,6 +1361,7 @@ def __setKnowledgeBaseAttributes(flushAll=True):
     kb.suppressSession = False
     kb.suppressResumeInfo = False
     kb.technique = None
+    kb.tested = []
     kb.testMode = False
     kb.testQueryCount = 0
     kb.threadContinue = True