diff --git a/lib/techniques/error/use.py b/lib/techniques/error/use.py
index ec3ce5eb6..bcd3436db 100644
--- a/lib/techniques/error/use.py
+++ b/lib/techniques/error/use.py
@@ -58,7 +58,7 @@ def __oneShotErrorUse(expression, field):
     offset = 1
     chunk_length = None
 
-    if not retVal:
+    if retVal is None:
         while True:
             check = "%s(?P<result>.*?)%s" % (kb.chars.start, kb.chars.stop)
             trimcheck = "%s(?P<result>.*?)</" % (kb.chars.start)
diff --git a/lib/techniques/union/use.py b/lib/techniques/union/use.py
index 3beac6d50..b1d65793e 100644
--- a/lib/techniques/union/use.py
+++ b/lib/techniques/union/use.py
@@ -52,7 +52,7 @@ def __oneShotUnionUse(expression, unpack=True, limited=False):
 
     retVal = conf.hashDB.retrieve(expression) if not conf.freshQueries else None
 
-    if not retVal:
+    if retVal is None:
         check = "(?P<result>%s.*%s)" % (kb.chars.start, kb.chars.stop)
         trimcheck = "%s(?P<result>.*?)</" % (kb.chars.start)