diff --git a/tsadar/process/prepare.py b/tsadar/process/prepare.py
index e6a45dd..387b880 100644
--- a/tsadar/process/prepare.py
+++ b/tsadar/process/prepare.py
@@ -22,9 +22,12 @@ def prepare_data(config: Dict) -> Dict:
 
     """
     # load data
-    custom_path = (config["data"]["filenames"]["epw"] is not None) | (config["data"]["filenames"]["iaw"] is not None)
-    if custom_path:
-        custom_path = os.path.dirname(config["data"]["filenames"]["epw"])
+    if "filenames" in config["data"].keys():
+        custom_path = (config["data"]["filenames"]["epw"] is not None) | (
+            config["data"]["filenames"]["iaw"] is not None
+        )
+        if custom_path:
+            custom_path = os.path.dirname(config["data"]["filenames"]["epw"])
 
     [elecData, ionData, xlab, config["other"]["extraoptions"]["spectype"]] = loadData(
         config["data"]["shotnum"], config["data"]["shotDay"], config["other"]["extraoptions"], custom_path=custom_path