Needed to set your Outlook (with an MS Exchange e-mail account) to ask you for your password each time you open it, here you go:
- Start Outlook.
- To View the accounts…
- In 2010/2013:
- Select the File tab.
- Click the Account Settings button.
- From the drop-down list, select Account Settings...
- Select your Exchange account.
- Click the More Settings... button.
- Select the Security tab.
- Place a check in the Always prompt for logon credentials check box.
- Click OK.
- Click the Cancel button.
- Click the Close button.
- Restart Outlook.