diff --git a/samples/qt/VoxelDemo/VoxelDemo.pro b/samples/qt/VoxelDemo/VoxelDemo.pro
index 1e68dc1416..93cf61dd54 100644
--- a/samples/qt/VoxelDemo/VoxelDemo.pro
+++ b/samples/qt/VoxelDemo/VoxelDemo.pro
@@ -162,4 +162,4 @@ LIBS += -lTKernel -lPTKernel -lTKMath -lTKService -lTKV3d \
         -lTKBRep -lTKGeomBase -lTKPShape -lTKTopAlgo -lTKPrim \
         -lTKBool -lTKVoxel -lTKOpenGl \
 
-
+QMAKE_CXXFLAGS            = -Zc:wchar_t