diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6597ec4..646082d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ All notable changes to this project will be documented in this file. The format
 ### Changed
 - find config.php automatically in current and parent directories. Show error message if not found. 
 - use local CSS/JS instead of CDN
+- detect missing imap extension and config error
 
 ## [0.2.1] - 2018-07-01
 
diff --git a/README.md b/README.md
index 3e00d1e..f4434b6 100644
--- a/README.md
+++ b/README.md
@@ -62,6 +62,11 @@ Install php dependecies:
 
     ini_set('display_errors', 1);    ini_set('display_startup_errors', 1);    error_reporting(E_ALL);
 
+## Testing on MacOs
+ * brew install php 
+ * brew install kabel/php-ext/php-imap
+ * php -S localhost:8000 -t src
+ 
 
 ## Credit :thumbsup:
 
diff --git a/src/boot.php b/src/boot.php
index 86ae958..f02b0f0 100644
--- a/src/boot.php
+++ b/src/boot.php
@@ -3,6 +3,8 @@ if (version_compare(phpversion(), '7.2', '<')) {
     die("ERROR! The php version isn't high enough, you need at least 7.2 to run this application! But you have: " . phpversion());
 }
 
+extension_loaded("imap") || die('ERROR: IMAP extension not loaded. Please see the installation instructions in the README.md');
+
 /**
  * searches for a config-file in the current and parent directories until found. 
  * @return path to found config file, or FALSE otherwise. 
@@ -32,6 +34,9 @@ function load_config(){
 	$file = find_config();
 	if ( $file !== FALSE) {
 		require_once($file);
+		if(!isset($config) || !is_array($config)){
+            die('ERROR: Config file is invalid. Please see the installation instructions in the README.md');
+        }
 	} else {
 		die('ERROR: Config file not found. Please see the installation instructions in the README.md');
 	}