OST File - Knowledgebase

Home » What is OST File

What is OST file?

OST is referred as the Offline Storage Table file which gets created automatically through MS Outlook offline folders feature. The OST file becomes active when Exchange connectivity gets offline and synchronizes all updated email information when Exchange turns online. After this process, MS Outlook turns online and all the saved emails and information is delivered to respective client immediately. That is, due to OST files, you can work offline as well and server is automatically synced. In certain cases, where network is limited or unreliable, creation of OST files proves to be an excellent process. Therefore, creation of OST files, permits user to work in server downtime situations as well.


How OST files work?

When you are working in an Offline mode, MS Outlook creates an exact copy of user mailbox on Exchange Server named as offline folders with OST file extension. The aforementioned file is saved locally on your desktop named as offline folder file. OST files are exact replica of the folders of an individual user mailbox on Exchange. Every modification made while working offline, is automatically synchronized when you are connected to Exchange Server.

Using the Send/Receive command, you can perform send or receive functions and copy the changes that were made while working offline. During this process, permanently deleted items get removed from the Exchange server’s copy as well. However, there could be several reasons to cause OST file corruption. There are many ways by which users can deal with OST corruption.

How to create an OST file?

When MS Outlook is run for the first time on a computer, it creates the important data files automatically. OST files are created as soon as you start working on MS Outlook. Outlook data files are saved at C:\Documents and Settings\Local Settings\Application Data\Microsoft\Outlook

If you wish to create an OST file yourself, then follow the instructions below:

  1. Click on the File Menu and select Work Offline option
  2. Offline file is created on your computer and all data from the server is copied to the new Offline Folder File (OST)
  3. Select folders for offline utilization. Usually Inbox, Outbox, Deleted Items, Sent Items, Calendar, Contacts and Task folders are automatically made available offline. In order to select any other folder, then follow the instructions given below:
    [A] On Tools menu > Send/Receive > Send/Receive Settings > Define Send/Receive Groups

    [B] In the list, click the Send/Receive group comprising of Exchange account and then click Edit.
    [C] Under Accounts, select your Exchange account.

    [D] Under Folders Options, select the folders that you want to use Offline.

Note- Here you can do one of the following:

  1. Select Download headers only (In this case OST file will not contain every file, but only a limited information so that you browse quickly through the OST file even when you are working online).
  2. Select Download complete item including attachments.
  3. Select Download only headers for items larger than to set limit on download of headers for items according to the specified size.
Advantages of using OST files
  1. OST files facilitates working on Outlook offline. Users across the globe use this method to keep their work safe and secure. (XXXDeleteXXX)
  2. OST files offers the flexibility to work offline without actually connecting to the server.
  3. In cases of accidental mailbox deletion or mailbox data corruption, OST file serves as a backup of your previous important email items. User can recover emails and save them in PST format anytime.

Thanks to all these advantages, user can work continuously and the data is safe even after server crashes and Exchange disasters.

How to recover data if the OST file gets corrupted?

In normal situations, the corruption of OST file is not an issue for Exchange administrators. Exchange will recreate healthy OST files when they delete the existing, damaged OST files. So if you find any issue with OST file data, just delete the OST file and let the Exchange recreate it.

How to retrieve Exchange mailboxes from OST files?

When Exchange database is corrupt, mailboxes become inaccessible to all the users. At this time, individual Exchange mailboxes can be restored from their corresponding OST files. However, OST files need to be converted to PST format for accessing them in Outlook or importing to another Exchange database/Office 365.

In such situations, the OST to PST converter freeware comes handy. The OST to PST converter freeware converts OST file to PST file in a couple of minutes and makes it possible to access emails, contacts, journals, notes, tasks etc., effortlessly. This tool can recover mailboxes even if the OST files are corrupt or highly damaged.

Salient Features of OST to PST Tool:Support

  • Quick conversion of inaccessible, unusable Offline Storage Table (OST) files to Personal Storage Table (PST) files.
  • Preserves complete email formatting, structure and properties.
  • Restores emails in Text, RTF, HTML, MHTML, PST, PDF, MBOX, DBX, IMAP, EML and MSG formats.
  • Embedded with fully interactive, user-friendly GUI, which doesn’t demand any technical skills to operate the software.
  • Supports all versions of MS Exchange Server, MS Outlook and Outlook Express.
  • Offers free Evaluation Version that can save 25 items from the recovered OST files.
  • Allows user to find particular email items using Find functionality.
  • Facilitates user to save email items just by selecting a date from a date range.
  • Recovers mail messages, folders, posts, appointments, contact addresses, tasks, meeting requests, journals, notes, calendar, drafts, Emails deleted from “Deleted Items” folder.
  • Recovers attachments like documents and images embedded in HTML.
  • Offers options for saving emails to web enabled email services like AOL, Hotmail, Live Mail, Google Apps, Yahoo, Outlook, iCloud, and Gmail.
  • Recovers Email properties such as Subject, To, From, Cc, Bcc, and date.
  • Recovers attachments like documents and images embedded in HTML.
  • Provision to migrate recovered files flawlessly to email servers like Office 365, IBM Domino, MS Exchange Server, and Novell GroupWise.
  • Comes with a 30 days’ money back guarantee.
  • Generates user-friendly graphical reports on mail flow density by date or senders, interaction between users, and total item types.
  • Free from viruses and is completely safe to be installed on the computer system.
  • Round-the-clock technical support.
  • Integrated with the Live Update feature that assures user to have feature-rich latest updated version.
  • Live Support feature assist users in operating the software efficiently.
Free OST to PST Conversion

If you want to recover a few of your important emails from corrupt OST files, you can try the free version of OST to PST Converter. It can save up to 25 emails from each folder of the OST file. And to save more items, you can license the software later.

Software Download
Recent Post on Blog
How to resolve Non-Synchronization Issue of Outlook OST?
In an organization having networking environment, numerous outlook users are connected with an Exchange domain server. Microsoft Exchange server links those Outlook user mailboxes with internet in order to establish a reliable environment for all incoming and outgoing emails.
read more...