How to Disable Forwarding in the Outlook Calendarby Greg Lindberg
As administrator on your computer, you can control specific functions for the Microsoft Office Outlook Task Manager application. For example, you can disable the reply to all and forwarding buttons within your application if you no longer want the option to be able to forward a message that you receive. Also, disabling forward will prevent recipients who receive your message or calendar from forwarding the items to other people, which can be helpful when you want to make sure your original message cannot be edited.
Click the "Start" button from your desktop and then select the "All Programs" option.
Double-click the "Microsoft Outlook" application from the list of programs, and the Outlook will open on your screen.
Select the "File" option from the top of the application if you're using Outlook 2003 or click the "Microsoft Office" button if you're using Outlook 2007.
Move your mouse over the "Permission" option and then select the "Do Not Forward" option.
Click the "Yes" button from the prompt that appears and then forwarding will be fully disabled in Outlook.