diff --git a/GUI/CMakeLists.txt b/GUI/CMakeLists.txt
index 3e235e473726193a969a0065fec71033fe0cdbed..10792fb54bc38097e5860ae801feafc8698e61fd 100644
--- a/GUI/CMakeLists.txt
+++ b/GUI/CMakeLists.txt
@@ -102,7 +102,7 @@ set(${library_name}_INCLUDE_DIRS ${include_dirs})
 set(${library_name}_LIBRARY ${library_name})
 
 # --- switch OFF Qt debug output in any configuration except DEBUG
-target_compile_definitions(${library_name} PUBLIC $<$<NOT:$<CONFIG:Debug>>:-DQT_NO_DEBUG_OUTPUT>)
+target_compile_definitions(${library_name} PUBLIC $<$<NOT:$<CONFIG:Debug>>:QT_NO_DEBUG_OUTPUT>)
 
 # --- dependencies ---------
 target_include_directories(${library_name} PUBLIC