diff --git a/qt6-after/qt6-migrated-legatus/Lts/Common/LtsSession/CMakeLists.txt b/qt6-after/qt6-migrated-legatus/Lts/Common/LtsSession/CMakeLists.txt
index 53da7fd9f..f66f4ce4e 100755
--- a/qt6-after/qt6-migrated-legatus/Lts/Common/LtsSession/CMakeLists.txt
+++ b/qt6-after/qt6-migrated-legatus/Lts/Common/LtsSession/CMakeLists.txt
@@ -37,9 +37,14 @@ SET(ltssession_SRCS
   lts_session.h
   lts_session.cpp
   lts_session_lock_handler.h
-  lts_session_lock_handler.cpp
 )
 
+# Only include lock_handler implementation when RTI is available
+# When BUILD_RTI=OFF, stub header provides inline implementations
+if(BUILD_RTI)
+  list(APPEND ltssession_SRCS lts_session_lock_handler.cpp)
+endif()
+
 NGL_ADD_LIBRARY2(WS LtsSession SHARED ${ltssession_SRCS})
 NGL_TARGET_INCLUDE_DIRECTORIES(LtsSession
   PUBLIC