diff --git a/winixd/Makefile b/winixd/Makefile
index 360a584..871d7b3 100644
--- a/winixd/Makefile
+++ b/winixd/Makefile
@@ -51,7 +51,13 @@ endif
 
 
 # for make install
-WINIX_INSTALL_DIR = /usr/local/winix
+ifndef WINIX_INSTALL_DIR
+WINIX_INSTALL_DIR=/usr/local/winix
+endif
+
+ifeq ($(WINIX_INSTALL_DIR),)
+$(error WINIX_INSTALL_DIR env variable cannot be empty)
+endif
 
 
 export CXX