diff --git a/chrome/content/zotero/xpcom/date.js b/chrome/content/zotero/xpcom/date.js
index a38b005f6b..c6be728e61 100644
--- a/chrome/content/zotero/xpcom/date.js
+++ b/chrome/content/zotero/xpcom/date.js
@@ -267,7 +267,7 @@ Zotero.Date = new function(){
 			} else {
 				// local style date (middle or little endian)
 				date.year = m[6];
-				var country = Zotero.locale.substr(3);
+				var country = Zotero.locale ? Zotero.locale.substr(3) : "US";
 				if(country == "US" ||	// The United States
 				   country == "FM" ||	// The Federated States of Micronesia
 				   country == "PW" ||	// Palau
@@ -668,7 +668,7 @@ Zotero.Date = new function(){
 	 */
 	function getLocaleDateOrder(){
 		if (!_localeDateOrder) {
-			switch (Zotero.locale.substr(-2)) {
+			switch (Zotero.locale ? Zotero.locale.substr(3) : "US") {
 				// middle-endian
 				case 'US': // The United States
 				case 'BZ': // Belize