What is an OST file?
An Outlook OST file, or Offline Outlook Data File, is a file that allows Microsoft Outlook to work in offline mode, without a connection to the server. It is normally created when you use Cached Exchange mode in Outlook.
When Outlook is configured to use an Exchange Server account, it creates a local copy of your mailbox data on your computer in the form of an OST file. This file contains a synchronized copy of your mailbox items, such as emails, contacts, calendar items, tasks, and notes.
The OST file enables you to access your mailbox data when you are offline, and any changes you make to the data are saved locally and automatically synchronized with the server the next time you connect to the network.
OST files are especially useful for users who work in areas with intermittent or no internet connectivity, or for those who want to work offline without losing access to their mailbox data. It is important to note that Outlook cannot open an OST file in Windows directly. You need a professional OST opener tool or convert the OST to PST to retrieve your mailbox items.
