diff --git a/browser/base/content/test/performance/browser_startup_mainthreadio.js b/browser/base/content/test/performance/browser_startup_mainthreadio.js
index 2d9f17fbb980..f21f60803832 100644
--- a/browser/base/content/test/performance/browser_startup_mainthreadio.js
+++ b/browser/base/content/test/performance/browser_startup_mainthreadio.js
@@ -231,11 +231,6 @@ const startupPhases = {
       condition: WIN,
       stat: 1,
     },
-    {
-      path: "XCurProcD:blocklist.xml",
-      condition: WIN,
-      stat: 1,
-    },
     {
       // bug 1534745
       path: "ProfD:cookies.sqlite-journal",
diff --git a/modules/libpref/init/all.js b/modules/libpref/init/all.js
index b939110b682a..849dfa5bcb88 100644
--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -2305,6 +2305,8 @@ pref("extensions.blocklist.enabled", true);
 // OneCRL freshness checking depends on this value, so if you change it,
 // please also update security.onecrl.maximum_staleness_in_seconds.
 pref("extensions.blocklist.interval", 86400);
+// Whether to use the XML backend (true) or the remotesettings one (false).
+pref("extensions.blocklist.useXML", false);
 // Required blocklist freshness for OneCRL OCSP bypass
 // (default is 1.25x extensions.blocklist.interval, or 30 hours)
 pref("security.onecrl.maximum_staleness_in_seconds", 108000);
diff --git a/toolkit/mozapps/extensions/Blocklist.jsm b/toolkit/mozapps/extensions/Blocklist.jsm
index 2f1d00aec9c7..e6d234996299 100644
--- a/toolkit/mozapps/extensions/Blocklist.jsm
+++ b/toolkit/mozapps/extensions/Blocklist.jsm
@@ -3239,7 +3239,7 @@ XPCOMUtils.defineLazyPreferenceGetter(
   Blocklist,
   "useXML",
   "extensions.blocklist.useXML",
-  true,
+  false,
   () => Blocklist.onUpdateImplementation(true)
 );