diff --git a/macosx/BlocklistDownloader.m b/macosx/BlocklistDownloader.m
index 42a8a49d0..0e62aa6e6 100644
--- a/macosx/BlocklistDownloader.m
+++ b/macosx/BlocklistDownloader.m
@@ -117,7 +117,9 @@ BlocklistDownloader * fDownloader = nil;
 
 - (void) download: (NSURLDownload *) download didFailWithError: (NSError *) error
 {
-    [fViewController setFailed: [error localizedDescription]];
+    const BOOL blankURL = [[[[download request] URL] absoluteString] isEqualToString: @""];
+    [fViewController setFailed: blankURL ? NSLocalizedString(@"An address of a blocklist is needed.", "blocklist fail message")
+                                    : [error localizedDescription]];
     
     [[NSUserDefaults standardUserDefaults] setObject: [NSDate date] forKey: @"BlocklistNewLastUpdate"];
     [[BlocklistScheduler scheduler] updateSchedule];
diff --git a/macosx/en.lproj/Localizable.strings b/macosx/en.lproj/Localizable.strings
index 42b7a6a3b..f5e6ac0ea 100644
Binary files a/macosx/en.lproj/Localizable.strings and b/macosx/en.lproj/Localizable.strings differ