diff --git a/install.sh b/install.sh
index e41b2fb..3b3b263 100755
--- a/install.sh
+++ b/install.sh
@@ -25,6 +25,12 @@ if [ -d "/etc/letsencrypt/" ] || [ -d "/opt/certbot/" ] || [ -f "/usr/bin/certbo
   exit 1
 fi
 
+if [ ! -f "/usr/local/bin/vhost.sh" ]; then
+  echo "NOTICE: This package requires that Vhost Stack is installed first."
+  echo "https://git.stack-source.com/msb/vhost-stack"
+  exit 1
+fi
+
 # Old apt installation instructions
 #apt-get update
 #DEBIAN_FRONTEND=noninteractive apt-get -y install certbot python3-certbot python3-certbot-apache