diff --git a/libretroshare/src/gxstrans/p3gxstrans.h b/libretroshare/src/gxstrans/p3gxstrans.h
index 47ef1020d..af79679d9 100644
--- a/libretroshare/src/gxstrans/p3gxstrans.h
+++ b/libretroshare/src/gxstrans/p3gxstrans.h
@@ -293,7 +293,7 @@ private:
 		enum CheckState { CheckStart, CheckChecking };
 
 	public:
-        GxsTransIntegrityCleanupThread(RsGeneralDataService *const dataService): mDs(dataService),mMtx("GxsTransIntegrityCheck") { mDone=false;}
+        explicit GxsTransIntegrityCleanupThread(RsGeneralDataService *const dataService): mDs(dataService),mMtx("GxsTransIntegrityCheck") { mDone=false;}
 
 		bool isDone();
 		void run();