diff --git a/htdocs/core/lib/functions.lib.php b/htdocs/core/lib/functions.lib.php
index 7097bd2abae..f3add9e66c8 100644
--- a/htdocs/core/lib/functions.lib.php
+++ b/htdocs/core/lib/functions.lib.php
@@ -221,7 +221,12 @@ function GETPOST($paramname,$check='',$method=0)
  */
 function dol_getprefix()
 {
-	if (isset($_SERVER["SERVER_NAME"]) && isset($_SERVER["DOCUMENT_ROOT"])) return dol_hash($_SERVER["SERVER_NAME"].$_SERVER["DOCUMENT_ROOT"].DOL_DOCUMENT_ROOT.DOL_URL_ROOT);
+	if (isset($_SERVER["SERVER_NAME"]) && isset($_SERVER["DOCUMENT_ROOT"]))
+	{
+		return dol_hash($_SERVER["SERVER_NAME"].$_SERVER["DOCUMENT_ROOT"].DOL_DOCUMENT_ROOT.DOL_URL_ROOT);
+		// Use this for a "clear" cookie name
+		//return dol_sanitizeFileName($_SERVER["SERVER_NAME"].$_SERVER["DOCUMENT_ROOT"].DOL_DOCUMENT_ROOT.DOL_URL_ROOT);
+	}
 	else return dol_hash(DOL_DOCUMENT_ROOT.DOL_URL_ROOT);
 }