diff --git a/lib/private/helper.php b/lib/private/helper.php
index 58cb1b88d6690fee4f1c35912a655cd04934fa66..e5d1fa9b513f39406a7b29eaf0a8f541ad17d57c 100644
--- a/lib/private/helper.php
+++ b/lib/private/helper.php
@@ -151,6 +151,7 @@ class OC_Helper {
 	 */
 	public static function mimetypeIcon($mimetype) {
 		$alias = array(
+			'application/octet-stream' => 'file', // use file icon as fallback
 			'application/xml' => 'code/xml',
 			'application/msword' => 'x-office/document',
 			'application/vnd.openxmlformats-officedocument.wordprocessingml.document' => 'x-office/document',