diff --git a/src/lib/sync.hpp b/src/lib/sync.hpp
index d7afce536..d62960a94 100644
--- a/src/lib/sync.hpp
+++ b/src/lib/sync.hpp
@@ -387,10 +387,10 @@ namespace lib {
     class Sync
       {
         typedef sync::Monitor<CONF> Monitor;
-        Monitor objectMonitor_;
+        mutable Monitor objectMonitor_;
         
         static Monitor&
-        getMonitor(Sync* forThis)
+        getMonitor(const Sync* forThis)
           {
             REQUIRE (forThis);
             return forThis->objectMonitor_;