diff --git a/lib/setup.php b/lib/setup.php
index de7fb492587..47f95a7ec81 100644
--- a/lib/setup.php
+++ b/lib/setup.php
@@ -36,7 +36,11 @@
 
 // Set language/locale of printed times (must be supported by OS)
 
-    setlocale ("LC_TIME", $CFG->locale);
+    if ($CFG->locale) {
+        setlocale ("LC_TIME", $CFG->locale);
+    } else {
+        setlocale ("LC_TIME", $CFG->lang);
+    }
 
 // Load up theme variables (colours etc)