diff --git a/src/sync.h b/src/sync.h
index 204734c273..ead2cdc67b 100644
--- a/src/sync.h
+++ b/src/sync.h
@@ -10,9 +10,9 @@
 #include <util/macros.h>
 
 #include <condition_variable>
-#include <thread>
 #include <mutex>
-
+#include <string>
+#include <thread>
 
 ////////////////////////////////////////////////
 //                                            //