If you cannot open your Outlook data file or suspect that the file is damaged, use the Inbox Repair tool (scanpst.exe) to repair errors in the file.

Outlook Data Files (.ost) are used when you have an Exchange account and want to work offline or use or use the default Cached Exchange Mode. This type of data file is also used for …

Describes how to investigate items in an Outlook Data File (.pst) and troubleshoot search issues.

To reduce the size of your Outlook Data File (.pst) or Offline Outlook Data File (.ost), you can manually compact the data file. Select your version of Outlook below to see instructions on …

You may have an Offline Folders (.ost) file, but that file is automatically recreated by Outlook when you add a new email account. You can't move that file from one computer to another.

Some accounts (IMAP, Microsoft Exchange Server, and Outlook.com) use an offline Outlook Data File (.ost). This is a synchronized copy of the messages saved on a server.

說明如何調查 Outlook 資料檔 (.pst) 中的項目，並針對搜尋問題進行疑難排解。

If you receive one or more of these error messages, you may experience performance issues until Outlook finishes the reconciliation process for the .ost file or for the .pst file.

You might have stored Outlook items in an Outlook Data File (.pst) that you created in classic Outlook. If you want to open or close a .pst file, you now can do that in a few simple steps from …

When you add a POP3 email account to Outlook or create archives or backup files from any of your accounts in Outlook, an Outlook Data File (.pst) may be created within your OneDrive.