diff --git a/nano/core_test/backlog.cpp b/nano/core_test/backlog.cpp
index a4384e15..48456557 100644
--- a/nano/core_test/backlog.cpp
+++ b/nano/core_test/backlog.cpp
@@ -72,10 +72,10 @@ block_list_t setup_independent_blocks (nano::test::system & system, nano::node &
  */
 TEST (backlog, population)
 {
+	nano::mutex mutex;
 	nano::test::system system{};
 	auto & node = *system.add_node ();
 
-	nano::mutex mutex;
 	std::unordered_set<nano::account> activated;
 
 	node.backlog.activate_callback.add ([&] (nano::transaction const & transaction, nano::account const & account, nano::account_info const & account_info, nano::confirmation_height_info const & conf_info) {