diff --git a/academic/wxmacmolplt/doinst.sh b/academic/wxmacmolplt/doinst.sh
index 9830478e8c..0fb9c8b686 100644
--- a/academic/wxmacmolplt/doinst.sh
+++ b/academic/wxmacmolplt/doinst.sh
@@ -8,7 +8,7 @@ fi
 
 if [ -e usr/share/icons/hicolor/icon-theme.cache ]; then
   if [ -x /usr/bin/gtk-update-icon-cache ]; then
-    /usr/bin/gtk-update-icon-cache usr/share/icons/hicolor >/dev/null 2>&1
+    /usr/bin/gtk-update-icon-cache -f usr/share/icons/hicolor >/dev/null 2>&1
   fi
 fi