diff --git a/platform/osx/os_osx.mm b/platform/osx/os_osx.mm
index 6e5629cae..f1159b057 100644
--- a/platform/osx/os_osx.mm
+++ b/platform/osx/os_osx.mm
@@ -1079,7 +1079,7 @@ static int translateKey(unsigned int key) {
 }
 
 // Translates a Pandemonium keycode back to a OSX keycode
-static unsigned int unmapKey(int key) {
+static unsigned int unmapKey(unsigned int key) {
 	for (int i = 0; i <= 126; i++) {
 		if (_osx_to_pandemonium_table[i] == key) {
 			return i;