diff -p -up invesalius3/invesalius/i18n.py.orig invesalius3/invesalius/i18n.py
--- invesalius3/invesalius/i18n.py.orig	2010-04-01 15:55:04.292973825 -0300
+++ invesalius3/invesalius/i18n.py	2010-04-01 15:56:13.863615536 -0300
@@ -45,8 +45,10 @@ def GetLocaleOS():
         if sys.platform == 'darwin':
             locale.setlocale(locale.LC_ALL, "")
             return locale.getlocale()[0]
-
-        return locale.getdefaultlocale()[0]
+        lc = locale.getdefaultlocale()[0]
+        if lc:
+            return lc
+        return 'en'
 
 def InstallLanguage(language):
     language_dir = os.path.abspath(os.path.join('..','locale'))