--- a/netwerk/base/Predictor.cpp
+++ b/netwerk/base/Predictor.cpp
@@ -2402,16 +2402,32 @@ Predictor::UpdateCacheability(nsIURI *so
 }
 
 void
 Predictor::UpdateCacheabilityInternal(nsIURI *sourceURI, nsIURI *targetURI,
                                       uint32_t httpStatus,
                                       const nsCString &method)
 {
   PREDICTOR_LOG(("Predictor::UpdateCacheability httpStatus=%u", httpStatus));
+
+  if (!mInitialized) {
+    PREDICTOR_LOG(("    not initialized"));
+    return;
+  }
+
+  if (!mEnabled) {
+    PREDICTOR_LOG(("    not enabled"));
+    return;
+  }
+
+  if (!mEnablePrefetch) {
+    PREDICTOR_LOG(("    prefetch not enabled"));
+    return;
+  }
+
   uint32_t openFlags = nsICacheStorage::OPEN_READONLY |
                        nsICacheStorage::OPEN_SECRETLY |
                        nsICacheStorage::CHECK_MULTITHREADED;
   RefPtr<Predictor::CacheabilityAction> action =
     new Predictor::CacheabilityAction(targetURI, httpStatus, method, this);
   nsAutoCString uri;
   targetURI->GetAsciiSpec(uri);
   PREDICTOR_LOG(("    uri=%s action=%p", uri.get(), action.get()));