diff --git a/config/corne.keymap b/config/corne.keymap
index 3e5a315..707a5b9 100644
--- a/config/corne.keymap
+++ b/config/corne.keymap
@@ -8,6 +8,8 @@
 #include <dt-bindings/zmk/keys.h>
 #include <dt-bindings/zmk/bt.h>
 
+#define HOST_OS 2  // set to 2 for macOS/Windows-Alt-Codes, default is 0 (Windows)
+
 #include "../zmk-nodefree-config/helper.h"
 #include "../zmk-nodefree-config/keypos_def/keypos_42keys.h"
 #include "../zmk-nodefree-config/international_chars/german.dtsi"