diff --git a/daemon/main/nzbget.cpp b/daemon/main/nzbget.cpp
index c4f27721..aabf69cc 100644
--- a/daemon/main/nzbget.cpp
+++ b/daemon/main/nzbget.cpp
@@ -19,6 +19,8 @@
  */
 
 
+#include <sys/file.h>
+
 #include "nzbget.h"
 #include "ServerPool.h"
 #include "Log.h"
@@ -932,7 +934,7 @@ void NZBGet::Daemonize()
 			error("Starting daemon failed: could not create lock-file %s", m_options->GetLockFile());
 			exit(1);
 		}
-		if (lockf(lfp, F_TLOCK, 0) < 0)
+		if (flock(lfp, LOCK_EX) < 0)
 		{
 			error("Starting daemon failed: could not acquire lock on lock-file %s", m_options->GetLockFile());
 			exit(1);