menu, click Data File Management . Click the data file that you want to compact, and then click Settings . The Account Settings command is on the Tools menu in Microsoft Office Outlook 2007. If you are using an earlier version of Outlook, the following instructions do not apply. Use the Help that is included with that product. If the title bar of the program that you are using displays Microsoft Outlook Express, you are using a program that is not the same as Outlook. See Help in Outlook Express for assistance. In the list, select Microsoft Exchange Server , and then click Change . Click More Settings . Click the Advanced tab, and then click Offline Folder File Settings . Click Compact Now . Notes To delete an item from both the online and offline folders, select the item, and then press DELETE. If you are using an Exchange account in Cached Exchange Mode, only the selected folder will be cleared from the local .ost file. The items on the server will be downloaded again to the .ost file on the next synchronization, if the folder is selected under Folder Options in Send/Receive Settings for the Exchange Server e-mail account. When you use Cached Exchange Mode, public folders favorites are not synchronized by default. If you choose to synchronize public folders, the size of your Offline Folder file (.ost) may increase significantly.