diff --git a/sohstationviewer/controller/processing.py b/sohstationviewer/controller/processing.py
index 95c38ee640dadaa591559309ccf8cdb8e921f2d4..4b46116690bdbd0a26c084d55ca672334e265758 100644
--- a/sohstationviewer/controller/processing.py
+++ b/sohstationviewer/controller/processing.py
@@ -166,7 +166,7 @@ def detect_data_type(list_of_dir: List[str]) -> Optional[str]:
 
     data_type_list = {d[0] for d in dir_data_type_dict.values()}
     if len(data_type_list) > 1:
-        dir_data_type_str = ', '. join(list(data_type_list))
+        dir_data_type_str = ', '. join(sorted(list(data_type_list)))
         msg = (f"There are more than one types of data detected:\n"
                f"{dir_data_type_str}\n\n"
                f"Please have only one data type for each loading.")