Advice and Solutions (Forum Knowledgebase) Disclaimer. Read before using materials. This article is about Kaspersky Endpoint Security for Windows (KES for Windows) Outlook add-in failure may be related to a KES upgrade. Step-by-step guide As the first step to quickly fix majority of the issues with Outlook add-in, unregister it and register again. Here is how to do it properly: Close Outlook if opened.  Execute