diff --git a/modules/libpref/src/init/all.js b/modules/libpref/src/init/all.js
index c21a5eb0dadc..dcb4190a878a 100644
--- a/modules/libpref/src/init/all.js
+++ b/modules/libpref/src/init/all.js
@@ -623,6 +623,8 @@ pref("javascript.options.methodjit.content", true);
 pref("javascript.options.methodjit.chrome",  true);
 pref("javascript.options.jitprofiling.content", true);
 pref("javascript.options.jitprofiling.chrome",  true);
+pref("javascript.options.pccounts.content", false);
+pref("javascript.options.pccounts.chrome",  false);
 pref("javascript.options.methodjit_always", false);
 pref("javascript.options.typeinference", true);
 // This preference limits the memory usage of javascript.