diff --git a/src/common/platform/posix/cocoa/i_system.mm b/src/common/platform/posix/cocoa/i_system.mm
index cef2d177b..267bac31d 100644
--- a/src/common/platform/posix/cocoa/i_system.mm
+++ b/src/common/platform/posix/cocoa/i_system.mm
@@ -122,7 +122,7 @@ void I_ShowFatalError(const char *message)
 }
 
 
-int I_PickIWad(WadStuff* const wads, const int numwads, const bool showwin, const int defaultiwad, int&)
+int I_PickIWad(WadStuff* const wads, const int numwads, const bool showwin, const int defaultiwad, int&, FString&)
 {
 	if (!showwin)
 	{