diff --git a/spaceapi/active.py b/spaceapi/active.py
--- a/spaceapi/active.py
+++ b/spaceapi/active.py
@@ -6,6 +6,12 @@ import os.path
 default_json_file = os.path.abspath('default.json')
 last_state_file = os.path.abspath('laststate.json')
 
+if not os.path.exists(default_json_file):
+    raise RuntimeError('default.json does not exists!')
+elif not os.path.isfile(default_json_file):
+    raise RuntimeError('defaul.json is not a file!')
+
+
 default_json = {}
 active_json = {}