diff --git a/tools/build/build.py b/tools/build/build.py
index bcb08748..d263cade 100755
--- a/tools/build/build.py
+++ b/tools/build/build.py
@@ -162,6 +162,7 @@ def build_oxjs(downloads=False, geo=False):
     for filename in sorted(os.listdir(source_path + js_dir)):
         if not filename in filenames \
                 and not filename.startswith('.') \
+                and not filename.startswith('_') \
                 and not filename.endswith('~'):
             filenames.append(filename)
     for filename in filenames:
@@ -191,12 +192,14 @@ def build_oxjs(downloads=False, geo=False):
     for path, dirnames, filenames in os.walk(root):
         for filename in sorted(filenames):
             # jquery gets included by Ox.UI loader
+            # locale json files are loaded lazily
             # Ox.UI.css imports all other css files
             # svgs are loaded as URLs or dataURLs
             # browser images appear before load
             if path != root and not '_' in path and not filename[0] in '._' \
                     and not filename.endswith('~') \
                     and not 'jquery' in filename \
+                    and not 'locale' in filename \
                     and not filename.endswith('theme.css') \
                     and not filename.endswith('.svg') \
                     and not filename.startswith('browser'):