diff --git a/singleapplication_p.cpp b/singleapplication_p.cpp
index 3b41391..7a98116 100644
--- a/singleapplication_p.cpp
+++ b/singleapplication_p.cpp
@@ -57,7 +57,9 @@
 #endif
 
 #ifdef Q_OS_WIN
-    #define NOMINMAX
+    #ifndef NOMINMAX
+        #define NOMINMAX 1
+    #endif
     #include <windows.h>
     #include <lmcons.h>
 #endif