diff --git a/toolkit/crashreporter/client/crashreporter_osx.h b/toolkit/crashreporter/client/crashreporter_osx.h
index 755e880908c..15599b90d9d 100644
--- a/toolkit/crashreporter/client/crashreporter_osx.h
+++ b/toolkit/crashreporter/client/crashreporter_osx.h
@@ -86,7 +86,7 @@
 - (void)showErrorUI:(const std::string&)dumpfile;
 - (void)showReportInfo;
 - (void)maybeSubmitReport;
-- (void)closeMeDown;
+- (void)closeMeDown:(id)unused;
 
 - (IBAction)submitReportClicked:(id)sender;
 - (IBAction)viewReportClicked:(id)sender;
diff --git a/toolkit/crashreporter/client/crashreporter_osx.mm b/toolkit/crashreporter/client/crashreporter_osx.mm
index 1cdc8e7174d..59196d408a8 100644
--- a/toolkit/crashreporter/client/crashreporter_osx.mm
+++ b/toolkit/crashreporter/client/crashreporter_osx.mm
@@ -236,7 +236,7 @@ static bool RestartApplication()
   }
 }
 
--(void)closeMeDown
+- (void)closeMeDown:(id)unused
 {
   [NSApp terminate:self];
 }