diff --git a/bin/set-colors b/bin/set-colors
index 837c1f8..47a085d 100755
--- a/bin/set-colors
+++ b/bin/set-colors
@@ -31,7 +31,7 @@ install_light() {
 postinstall() {
     "${DOTFILES}/alacritty/install"
 
-    if [ "${OSTYPE}" == 'Linux' ] && [ "${XDG_SESSION_TYPE}" != 'wayland' ]; then
+    if [ "${OSTYPE}" == 'Linux' ] && [ "${XDG_SESSION_TYPE-}" != 'wayland' ]; then
         killall --signal HUP xsettingsd
     fi
 }