Reduce the size of an Offline Folder file (.ost)

Do either of the following:

Reduce the size of an .ost

1. On the Tools menu, click E-mail accounts, click View or change existing e-mail accounts, and then click Next.
2. In the Outlook processes e-mail for these accounts in the following order list, select Microsoft Exchange Server, and then click Change.
3. Click More Settings.
4. Click the Advanced tab, and then click Offline Folder File Settings.
5. Click Compact Now.

Note   Reducing the size of an .ost may improve performance if you have deleted a large quantity of items.

Delete all items from an .ost

1. Right-click Inbox, and then click Properties on the shortcut menu.
2. Click Clear Offline Items.