diff --git a/Tools/nib2cib/Converter+Mac.j b/Tools/nib2cib/Converter+Mac.j
index 90e9cf062..15250f455 100644
--- a/Tools/nib2cib/Converter+Mac.j
+++ b/Tools/nib2cib/Converter+Mac.j
@@ -54,7 +54,7 @@
             else
                 cibFont = [NSFont cibFontForNibFont:[object font]];
 
-            if (![cibFont isEqual:nibFont])
+            if (!cibFont || ![cibFont isEqual:nibFont])
             {
                 var source = "";