An urgent need to import Contacts from OST file may arise when Exchange Admin wants a prospect’s contact information from an ex-employee’s mailbox which is available in OST file. In this blog, we’ll share as to how you can import contacts from OST file by using the default method which works when the OST file is associated with an Exchange account. Further, we will also share a method to import contacts from inaccessible or orphaned OST files. 

Before going through these methods for importing contacts from OST file, let’s first look at a few practical scenarios wherein you may need to import contacts from OST file.  

  1. Recover contacts from an old OST file: An organization has gone out of business. As a result, the Exchange server is also decommissioned. Though emails are available in a PST on local drives, the user may also want to recover the Contacts which are particularly available in the OST file. 
  1. Extract Outlook contacts from OST file: An administrator formatted the computer before exporting contacts for a user. However, the backup of entire folder is available on the local system. The email client is hosted on Exchange server and there is an immediate need to import contacts ASAP. 
  1. Restore Contacts from previous OST: An Outlook user had made changes in Outlook contacts and now wants to undo the changes. There is no PST file for the data. The backups are available as OST, NST (Outlook data file created by using Outlook connector for IBM Lotus Domino) and OAB (Offline Address Book) files before saving the final changes. 

It’s important to note that, by default, Exchange accounts (Outlook 2013 and later) accounts, IMAP accounts, and Office 365 accounts store their information in Offline Storage Tables or OST. Only POP accounts save their data in PST file. 

You can import contacts from an OST file with the help of following steps:

Method 1: Import Contacts in CSV format 

Note: This method works in case of a normal OST file that has an account associated with Exchange, O365, IMAP, or Outlook. This process will not work when the OST file is in an orphaned or inaccessible state. For importing contacts from inaccessible OST, use method 3.

  1. Check the Outlook version. The steps to import contacts from OST file are different for different Outlook versions, and also for the Outlook on the web. 

The following steps help in importing the data when the OST file is accessible.

  1. Go to Outlook and select the File tab from the main menu
This is what the ribbon looks like in Outlook 2016.
  1. Choose the option – Open & Export and then choose Import/Export
  2. Select the option Import from another program or file, and then select Next
  3. Select the option Comma Separated Values ((CSV) and click Next
  4. A new window will appear – Import to a file. Browse to your Contacts file and double click to select the file
When you import Gmail contacts to your Office 365 mailbox, click the Finish button to start the migration
  1. Select the radio button to include or exclude duplicates
  2. A window Select a Destination folder will appear. Select the Contacts folder and click next.
  3. For multiple email accounts, click the Contacts folder which is under the email account, to be associated with the Contacts. 
  4. Click Finish and the Outlook begins importing the Contacts from OST file immediately. 
  5. Verify the contacts from the People icon, available at the bottom of the Outlook interface.  
Choose the People icon at the bottom of the page.
  1. Steps differ as per the Exchange version. Verify the Outlook version to use the right method. 

Method 2: Import Contacts from Exchange Server

Exchange administrators can import contacts from mailboxes available in the EDB file. But, this method involves writing lengthy scripts on the Exchange server, which may be a tedious and time-taking task. And, in case the Exchange server is down, then importing contacts by using the scripts is not possible. Moreover, this method is not workable with IMAP and connectivity. 

Method 3: Import Contacts with the help of OST Converter Software

With the help of an OST to PST converter software such as Stellar Converter for OST, you can locate the OST file and import contacts. Whether the OST file is in the normal or inaccessible state, the software imports all contacts in a few simple steps, as follows: 

  1. Install and open Stellar Converter for OST
  1. Click Browse to locate the OST file in your system. If the location is not known, the software suggests the drives where you can find the OST file. Click Find to search for the OST file. 

Note: The Find feature is useful because many Outlook users are not aware of the location of their OST file. 

  1. Once selected, click Convert, and the software starts scanning and converting the OST file 
  2. One the file is scanned, the software displays a preview of the entire OST file data. Verify that the Contacts are intact and available.
  3. Select the Contacts folder click the Save Converted File button available in the main menu
  4. Select the file format to save Contacts folder and select the location
  5. The selected Outlook data is saved at the specified location.
  1. Verify that the data is available at the specified location. 


Working with Outlook in offline mode creates an Offline Storage Table or OST. Any change made in this OST file is automatically synced when the network connection re-establishes. Thus, an OST file is a copy of the entire elements saved on the corresponding mail server. This characteristic of the mail server and the OST file frees the administrator from backing-up the OST file data. However, users can create a copy of the OST file at a specified location. 

In IMAP, Exchange, and there is an option to save OST data in PST format, but many users are unaware of this feature and get stuck when the need to import contacts from OST file arises. Though it is easy to import data when the Outlook profile and OST file is accessible, the issue occurs when an OST file is found to be inaccessible or orphaned. 

Users can import contacts from an orphaned, inaccessible, or in an encrypted state by using an OST conversion tool. The software also works on IMAP OST files. 



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