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How to Open OST File without Outlook/Exchange in Offline Mode?

Raj | Modified: March 9th, 2023 | 3 Minutes Reading

Whether your Exchange OST file is inaccessible or orphaned. You are looking for a way to open OST file without Exchange or Outlook environment. Then, in this article, we will discuss the best ways to access offline OST files.

What is Offline OST File?

OST is an offline Outlook data file and cannot be opened directly in any Microsoft Outlook profile or email account. This is an encrypted file created while setting up Exchange, IMAP, Office 365, Hotmail account in Outlook. This file is attached to the specific profile and the computer on which you have configured the email account.

Unable to Open OST File in Offline Mode: Reasons

When email clients connect to Exchange Server with cached mode, an offline Outlook (.ost) folder file will be created. Even if an Outlook profile is configured as an Exchange mailbox, you can still access the OST file. If the Exchange Server account is deleted or inaccessible, the OST file will be damaged. Additionally, synchronization issues between the Exchange Server and an Outlook email client may cause the OST file to be orphaned. Even some users report of unable to see OST file in chrome, firefox, or edge browser.

OST File Corruption Due to the Following Reasons:

  • Virus or malware infection.
  • The Outlook application closes abruptly.
  • MS Outlook account was accidentally deleted on the Exchange Server.
  • The storage medium is defective.
  • When Exchange account was accidentally deleted.

Hassle-Free  Solution to Open OST File in Offline Mode

An advanced free OST file viewer that allows you to displays OST files in offline mode. Using the software, you can easily open offline data file, such as emails, contacts, calendars, etc., without having Outlook or Exchange environment. This tool allows users to access OST files in a hassle-free way, even password-protected, damaged encrypted files in Windows 10, 8, 7 (32 bit or 64 bit) and Windows Server 2016, 2012 R2, 2008.

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Best Features of the Software

  • Open emails, contacts, calendars, tasks, notes and journals of OST files
  • Access OST files with related emails with attachments without Outlook & Exchange Server
  • Professional version with 7+ viewing modes (Mail, Hex, HTML, Header, etc.) for in-depth email analysis
  • The tool is designed to open standard, encrypted, damaged, password protected OST files
  • Upgrade Pro version to export, print, search emails in OST files options

Note: If your OST file is heavily corrupted and inaccessible. You must be recover the file before restore it into Outlook. Use OST Recovery Software to repair corrupted OST file without any limitations and data loss.

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4 Step Process to Open OST File in Offline Mode on Windows OS

You just follow the 4 step process to open offline data files without Exchange and Outlook environment in offline mode:

1. Open Offline Software on Windows OS

Offline Viewer to Open OST File in Chrome

2. Next, Browse and Add OST File in Software Interface

Open OST File

3. Open OST File in Offline Mode without Any Limitations

Open OST File in Offline Mode

4. Upgrade to Pro Version for Export, Print, and Search Features


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OST files allow you to access mailbox data in offline mode. However, in case of Exchange Server crashes or any other problems, you may have problems accessing the OST file. Therefore, in this blog, we discussed ways to open OST file without Outlook or Exchange in offline mode.