One of the consultants working on a project for us recently took a week off. When he returned, he found that our SharePoint Online sites in our Office 365 Tenant no longer had this file: /_layouts/15/MicrosoftAjax.js . However, he still saw the file on other Office 365 tenants that he had access to. We promptly opened a ticket with Microsoft Premier support and found out that they removed this file, without notice, because of an update to Excel services: the microsoftajax.js file was previously used ......