To open an Outlook Data File (.pst), go to Settings > Files > Outlook Data Files. Select Add file. Select a .pst file and then select Open. Opening .pst files in new Outlook requires classic Outlook to also be …

Mar 3, 2026 · In today’s modern workplace, where email access needs to work both online and offline, Outlook relies on a special file format called the Offline Storage Table (.OST). This file allows you to …

Learn what an OST file is, how it works in Outlook, key differences from PST, plus safe ways to open, convert, back up, and recover corrupted OST files.

Feb 22, 2026 · An OST file (Offline Storage Table) is a local cache file created by Outlook so you can work with mailbox content even when the network is slow or unavailable. Outlook synchronizes the …

Mar 20, 2026 · OST (offline storage table) is a local copy of Exchange or Outlook 365 mailbox data that allows you to access emails and other items when you’re not connected to the internet. The OST file …

Dec 2, 2024 · The local file is known as an Offline Storage Table, or OST file for short. It allows you to access your emails, contacts and calendar even if you don’t have an internet con­nec­tion.

Jul 20, 2025 · What is OST File - A complete overview of Off line storage table with the steps to open OST file in Outlook or Without Outlook.

Apr 6, 2018 · An OST file is a data file created by Microsoft Outlook (2005 or later), an email client and personal information manager. It is used to store a copy of mailbox information from an Office 365, …

You can configure Outlook to keep a local copy of your items on your computer in an Outlook data file that is named an offline Outlook Data File (.ost). This allows you to use Cached Exchange Mode or …

Apr 4, 2025 · Offline Storage Table (.ost) Files: Made for IMAP, Exchange, or Microsoft 365 accounts, these hold a synced copy of what’s on the server so you can use Outlook offline.