diff --git a/src/app/valentina/dialogs/dialogknownmaterials.cpp b/src/app/valentina/dialogs/dialogknownmaterials.cpp
index 312fec1dd..a1ddf1157 100644
--- a/src/app/valentina/dialogs/dialogknownmaterials.cpp
+++ b/src/app/valentina/dialogs/dialogknownmaterials.cpp
@@ -29,6 +29,10 @@
 #include "dialogknownmaterials.h"
 #include "ui_dialogknownmaterials.h"
 
+#ifdef Q_CC_MSVC
+    #include <ciso646>
+#endif /* Q_CC_MSVC */
+
 //---------------------------------------------------------------------------------------------------------------------
 DialogKnownMaterials::DialogKnownMaterials(QWidget *parent)
     : QDialog(parent),