diff --git a/tanner/session_manager.py b/tanner/session_manager.py
index 8d3e613e..360c8b89 100644
--- a/tanner/session_manager.py
+++ b/tanner/session_manager.py
@@ -71,7 +71,8 @@ async def delete_old_sessions(self, redis_client):
             if not sess.is_expired():
                 continue
             await sess.remove_associated_db()
-            await sess.remove_associated_env()
+            if sess.associated_env is not None:
+                await sess.remove_associated_env()
             self.sessions.remove(sess)
             try:
                 await redis_client.set(sess.get_uuid(), sess.to_json())