diff --git a/chrome/content/zotero/xpcom/translation/translate.js b/chrome/content/zotero/xpcom/translation/translate.js
index ac2dd7f02..2ae8355f9 100644
--- a/chrome/content/zotero/xpcom/translation/translate.js
+++ b/chrome/content/zotero/xpcom/translation/translate.js
@@ -1045,7 +1045,7 @@ Zotero.Translate.Base.prototype = {
 		this._currentState = "translate";
 		
 		if(!this.translator || !this.translator.length) {
-			throw new Error("Failed: no translator specified");
+			this.complete(false, new Error("No translator specified"));
 		}
 		
 		this._libraryID = libraryID;
@@ -2093,8 +2093,8 @@ Zotero.Translate.Search.prototype.setTranslator = function(translator) {
  */
 Zotero.Translate.Search.prototype.complete = function(returnValue, error) {
 	if(this._currentState == "translate" && (!this.newItems || !this.newItems.length)) {
-		Zotero.debug("Translate: Could not find a result using "+this.translator[0].label+": \n"
-					  +this._generateErrorString(error), 3);
+		Zotero.debug("Translate: Could not find a result using "+this.translator[0].label, 3);
+		if(error) Zotero.debug(this._generateErrorString(error), 3);
 		if(this.translator.length > 1) {
 			this.translator.shift();
 			this.translate(this._libraryID, this._saveAttachments);
diff --git a/chrome/content/zotero/xpcom/utilities.js b/chrome/content/zotero/xpcom/utilities.js
index a5622c66f..e2f3cab5b 100644
--- a/chrome/content/zotero/xpcom/utilities.js
+++ b/chrome/content/zotero/xpcom/utilities.js
@@ -277,7 +277,10 @@ Zotero.Utilities = {
 	 * Return isbn if valid, otherwise return false
 	 */
 	"cleanISBN":function(/**String*/ isbn) {
-		isbn = isbn.replace(/[^x\d]+/ig, '').toUpperCase();
+		isbn = isbn.replace(/[^0-9a-z]+/ig, '').toUpperCase()	//we only want to ignore punctuation, spaces
+						.match(/(?:97[89][0-9]{10}|[0-9]{9}[0-9X])/);	//13 digit or 10 digit
+		if(!isbn) return false;
+		isbn = isbn[0];
 
 		if(isbn.length == 10) {
 			// Verify ISBN-10 checksum
@@ -292,17 +295,11 @@ Zotero.Utilities = {
 			return (sum % 11 == 0) ? isbn : false;
 		}
 
-		isbn = isbn.replace(/X/g, '');	//get rid of Xs
-
 		if(isbn.length == 13) {
-			// ISBN-13 should start with 978 or 979 i.e. GS1 for book publishing industry
-			var prefix = isbn.slice(0,3);
-			if (prefix != "978" && prefix != "979") return false;
-
 			// Verify checksum
 			var sum = 0;
 			for (var i = 0; i < 12; i+=2) sum += isbn[i]*1;	//to make sure it's int
-			for (i = 1; i < 12; i+=2) sum += isbn[i]*3;
+			for (var i = 1; i < 12; i+=2) sum += isbn[i]*3;
 			sum += isbn[12]*1; //add the check digit
 
 			return (sum % 10 == 0 )? isbn : false;