diff --git a/htdocs/install/inc.php b/htdocs/install/inc.php
index 88dbc76f9a6..c1581d37392 100644
--- a/htdocs/install/inc.php
+++ b/htdocs/install/inc.php
@@ -566,7 +566,7 @@ function detect_dolibarr_main_url_root()
 		$dolibarr_main_url_root = $_SERVER["SERVER_URL"] . $_SERVER["DOCUMENT_URI"];
 	} // If SCRIPT_URI, SERVER_URL, DOCUMENT_URI not defined (Ie: Apache 2.0.44 for Windows)
 	else {
-		$proto = 'http';
+        $proto = ( (!empty($_SERVER["HTTPS"]) && $_SERVER["HTTPS"] == 'on') || $_SERVER['SERVER_PORT'] == 443) ? 'https' : 'http';
 		if (!empty($_SERVER["HTTP_HOST"])) {
 			$serverport = $_SERVER["HTTP_HOST"];
 		} else {