--- a/toolkit/xre/nsAppRunner.cpp
+++ b/toolkit/xre/nsAppRunner.cpp
@@ -4862,21 +4862,24 @@ MultiprocessBlockPolicy() {
     uint32_t difference = now - a11yRunDate;
     if (difference > ONE_WEEK_IN_SECONDS || !a11yRunDate) {
       Preferences::ClearUser(kAccessibilityLastRunDatePref);
     } else {
       disabledForA11y = true;
     }
   }
 
+  bool doAccessibilityCheck = true;
+#if defined(MOZ_WIDGET_GTK) && !defined(RELEASE_OR_BETA)
   // For linux nightly and aurora builds skip accessibility
   // checks.
-  bool doAccessibilityCheck = true;
-#if defined(MOZ_WIDGET_GTK) && !defined(RELEASE_OR_BETA)
   doAccessibilityCheck = false;
+#elif defined(XP_WIN)
+  // For Windows Vista and up, skip accessibility checks.
+  doAccessibilityCheck = !IsVistaOrLater();
 #endif
 
   if (doAccessibilityCheck && disabledForA11y) {
     gMultiprocessBlockPolicy = kE10sDisabledForAccessibility;
     return gMultiprocessBlockPolicy;
   }
 
   /**