diff --git a/TestON/drivers/common/cli/emulator/mininetclidriver.py b/TestON/drivers/common/cli/emulator/mininetclidriver.py
index 3eb5577..b38e257 100644
--- a/TestON/drivers/common/cli/emulator/mininetclidriver.py
+++ b/TestON/drivers/common/cli/emulator/mininetclidriver.py
@@ -2321,6 +2321,8 @@
         try:
             main.log.info( "Getting flows from Mininet" )
             flows = self.getFlowTable( sw, version, debug )
+            if flows == None:
+                return main.ERROR
 
             if debug: print "flow ids:\n{}\n\n".format(flowId)