diff --git a/src/main/clojure/clojask/dataframe.clj b/src/main/clojure/clojask/dataframe.clj
index d0c88c9..48bd325 100644
--- a/src/main/clojure/clojask/dataframe.clj
+++ b/src/main/clojure/clojask/dataframe.clj
@@ -688,6 +688,8 @@
   (assert (or (nil? select) (nil? exclude)) "can only specify either of them")
   ;; check if output-dir clashes with input file path
   (.checkInputPathClash this output-dir)
+  ;; initialise file
+  (u/init-file output-dir)
   ;; check which type of dataframe this is
   (let [exclude (if (coll? exclude) exclude [exclude])
         select (if select select (if (not= [nil] exclude) (doall (remove (fn [item] (.contains exclude item)) (.getColNames this))) nil))]
diff --git a/src/main/clojure/clojask/groupby.clj b/src/main/clojure/clojask/groupby.clj
index 8d2c7b2..8805af2 100644
--- a/src/main/clojure/clojask/groupby.clj
+++ b/src/main/clojure/clojask/groupby.clj
@@ -1,6 +1,6 @@
 (ns clojask.groupby
   (:require [clojure.java.io :as io]
-            [clojure-csv.core :as csv]
+            ;[clojure-csv.core :as csv]
             [clojask.utils :as u]
             [clojure.core.async :as async]))
 "contains the utility functions to group by and aggregate"