diff --git a/layout/generic/crashtests/crashtests.list b/layout/generic/crashtests/crashtests.list
index f0958c295dc..5fb6e612400 100644
--- a/layout/generic/crashtests/crashtests.list
+++ b/layout/generic/crashtests/crashtests.list
@@ -293,7 +293,7 @@ load 495875-1.html
 load 495875-2.html
 load 499862-1.html
 load 499857-1.html
-asserts(15) asserts-if(MOZ_WIDGET_TOOLKIT=="windows",18) load 499885-1.xhtml # nscoord_MAX assertions, plus bug 570436 on windows
+asserts(15) asserts-if(MOZ_WIDGET_TOOLKIT=="windows",18) asserts-if(MOZ_WIDGET_TOOLKIT=="cocoa",10) load 499885-1.xhtml # nscoord_MAX assertions, plus bug 570436 on windows
 load 501535-1.html
 load 503961-1.xhtml
 load 503961-2.html