--- a/toolkit/components/url-classifier/Classifier.cpp
+++ b/toolkit/components/url-classifier/Classifier.cpp
@@ -616,16 +616,18 @@ void
 Classifier::RemoveUpdateIntermediaries()
 {
   // Remove old LookupCaches.
   for (auto c: mNewLookupCaches) {
     delete c;
   }
   mNewLookupCaches.Clear();
 
+  mNewTableFreshness.Clear();
+
   // Remove the "old" directory. (despite its looking-new name)
   if (NS_FAILED(mUpdatingDirectory->Remove(true))) {
     // If the directory is locked from removal for some reason,
     // we will fail here and it doesn't matter until the next
     // update. (the next udpate will fail due to the removable
     // "safebrowsing-udpating" directory.)
     LOG(("Failed to remove updating directory."));
   }
@@ -680,26 +682,31 @@ Classifier::SwapInNewTablesAndCleanup()
     return rv;
   }
 
   // Step 2. Merge mNewLookupCaches into mLookupCaches. The outdated
   // LookupCaches will be stored in mNewLookupCaches and be cleaned
   // up later.
   MergeNewLookupCaches();
 
-  // Step 3. Re-generate active tables based on on-disk tables.
+  // Step 3. Merge mTableFreshnessForUpdate.
+  for (auto itr = mNewTableFreshness.ConstIter(); !itr.Done(); itr.Next()) {
+    mTableFreshness.Put(itr.Key(), itr.Data());
+  }
+
+  // Step 4. Re-generate active tables based on on-disk tables.
   rv = RegenActiveTables();
   if (NS_FAILED(rv)) {
     LOG(("Failed to re-generate active tables!"));
   }
 
-  // Step 4. Clean up intermediaries for update.
+  // Step 5. Clean up intermediaries for update.
   RemoveUpdateIntermediaries();
 
-  // Step 5. Invalidate cached tableRequest request.
+  // Step 6. Invalidate cached tableRequest request.
   mIsTableRequestResultOutdated = true;
 
   LOG(("Done swap in updated tables."));
 
   return rv;
 }
 
 void Classifier::FlushAndDisableAsyncUpdate()
@@ -1294,17 +1301,17 @@ Classifier::UpdateHashStore(nsTArray<Tab
 #if defined(DEBUG)
   lookupCache->DumpCompletions();
 #endif
   rv = lookupCache->WriteFile();
   NS_ENSURE_SUCCESS(rv, NS_ERROR_UC_UPDATE_FAIL_TO_WRITE_DISK);
 
   int64_t now = (PR_Now() / PR_USEC_PER_SEC);
   LOG(("Successfully updated %s", store.TableName().get()));
-  mTableFreshness.Put(store.TableName(), now);
+  mNewTableFreshness.Put(store.TableName(), now);
 
   return NS_OK;
 }
 
 nsresult
 Classifier::UpdateTableV4(nsTArray<TableUpdate*>* aUpdates,
                           const nsACString& aTable)
 {
@@ -1396,17 +1403,17 @@ Classifier::UpdateTableV4(nsTArray<Table
     LOG(("Write meta data of the last applied update."));
     rv = lookupCache->WriteMetadata(lastAppliedUpdate);
     NS_ENSURE_SUCCESS(rv, NS_ERROR_UC_UPDATE_FAIL_TO_WRITE_DISK);
   }
 
 
   int64_t now = (PR_Now() / PR_USEC_PER_SEC);
   LOG(("Successfully updated %s\n", PromiseFlatCString(aTable).get()));
-  mTableFreshness.Put(aTable, now);
+  mNewTableFreshness.Put(aTable, now);
 
   return NS_OK;
 }
 
 nsresult
 Classifier::UpdateCache(TableUpdate* aUpdate)
 {
   if (!aUpdate) {

--- a/toolkit/components/url-classifier/Classifier.h
+++ b/toolkit/components/url-classifier/Classifier.h
@@ -209,16 +209,17 @@ private:
   nsCOMPtr<nsIFile> mUpdatingDirectory; // For update only.
   nsCOMPtr<nsIFile> mToDeleteDirectory;
   nsCOMPtr<nsICryptoHash> mCryptoHash;
   nsTArray<LookupCache*> mLookupCaches; // For query only.
   nsTArray<nsCString> mActiveTablesCache;
   uint32_t mHashKey;
   // Stores the last time a given table was updated (seconds).
   TableFreshnessMap mTableFreshness;
+  TableFreshnessMap mNewTableFreshness;
 
   // In-memory cache for the result of TableRequest. See
   // nsIUrlClassifierDBService.getTables for the format.
   nsCString mTableRequestResult;
 
   // Whether mTableRequestResult is outdated and needs to
   // be reloaded from disk.
   bool mIsTableRequestResultOutdated;