diff --git a/api/src/Sharing.php b/api/src/Sharing.php
index 496b2ed928..b6e801156d 100644
--- a/api/src/Sharing.php
+++ b/api/src/Sharing.php
@@ -507,7 +507,7 @@ class Sharing
 	public function ServeRequest()
 	{
 		// sharing is for a different share, change to current share
-		if (empty($this->share['skip_validate_token']) && $this->share['share_token'] !== self::get_token())
+		if (empty($this->share['skip_validate_token']) && self::get_token() && $this->share['share_token'] !== self::get_token())
 		{
 			// to keep the session we require the regular user flag "N" AND a user-name not equal to "anonymous"
 			self::create_session($GLOBALS['egw']->session->session_flags === 'N' &&