To change your work days and times, follow these steps:
- In Outlook, click the File tab.
- Click Options, and then click Calendar.
- In the Start time and End time lists under Work time, click the Start time and End time of your work day. These are used primarily for your free/busy availability times for meeting requests from other people:
If no users have working hours that span midnight, the issue may be related to the one that's described in the following KB article:
Article ID: 2997998 - Last Review: 5 Jan 2015 - Revision: 1