diff --git a/app/controllers/chunks_controller.rb b/app/controllers/chunks_controller.rb
index 0752a533e52be006ae32d845314245282f7646b4..be663c6f83cc362d0027c3bd32f31a05e7120ccb 100644
--- a/app/controllers/chunks_controller.rb
+++ b/app/controllers/chunks_controller.rb
@@ -109,7 +109,7 @@ class ChunksController < ApplicationController
   end
 
   def resumable_file_extension
-    File.extname(chunks_params[:resumableFilename]).tr('.','')
+    File.extname(chunks_params[:resumableFilename])[1..-1]
   end
 
   def valid_mime_type?