diff --git a/eb_hooks.py b/eb_hooks.py
index e8afdc75d9..0280c325c8 100644
--- a/eb_hooks.py
+++ b/eb_hooks.py
@@ -136,6 +136,8 @@ def post_ready_hook(self, *args, **kwargs):
         parallel_param = 'max_parallel'
     # get current parallelism setting
     parallel = self.cfg[parallel_param]
+    if parallel == None:
+        return  # self.cfg doesn't contain 'parallel' or 'max_parallel'
     if parallel == 1:
         return  # no need to limit if already using 1 core