diff --git a/conanfile.py b/conanfile.py
index 8bf0df0..ea8f5e2 100644
--- a/conanfile.py
+++ b/conanfile.py
@@ -16,7 +16,8 @@ class CreatureLibConan(ConanFile):
     def build(self):
         cmake = CMake(self)
         if self.settings.get_safe("os") == "Windows":
-            cmake.definitions["WINDOWS"] = True
+            self.output.warn("Noticed Windows target, setting Cmake WINDOWS=On.")
+            cmake.definitions["WINDOWS"] = "On"
         cmake.configure()
         cmake.build()