These instructions apply to Microsoft Outlook for Microsoft 365, Outlook 2016. Select the links to the Microsoft documentation to learn more about each topic.
- In a Microsoft Exchange Server account, you can decide how much mail is available when working offline with a slow or no network connection. Read more on the topic in this Microsoft article Change how much mail to keep offline.
- Email messages, calendar, tasks, and other items are saved on a mail server, on your computer, or both. Outlook items that are saved on your computer, are kept in an Outlook Data File (.pst and .pst). Find out more in this Microsoft article Manage and Organize with Data Files.
- When your online mailbox is near your storage quota, you could move some items to an Outlook Data File (.pst). Older messages and items that you don't use regularly can be archived in an Outlook Data File (.pst). More information is found in Microsoft's Create an Outlook Data File (.pst) to save your information article.
- An Outlook Data File (.pst) contains your backed-up email messages, calendars, contacts, tasks, and notes, and can be stored in one of the default locations. Visit Microsoft's Locating the Outlook data files article.
- You can move old items you want to keep to an archive, which is a separate Outlook Data File (.pst) that you can open from Microsoft Outlook anytime you need it. For more information, read these Microsoft articles: