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How to use OST Viewer tool to Open OST file without Outlook?

Access/Read Outlook items from OST files & Convert/Migrate OST files into multiple conversion formats.


Try eSoftTools Free OST Viewer Software and easily view OST file content without Outlook. Directly access offline/corrupt/inaccessible/ encrypted/ orphaned OST files. View all emails, contacts, calendar, and other mailbox items from OST files. Also, convert/migrate OST files to different conversion formats and cloud mail apps using this single software.

Step-1) Download & Launch eSoftTools Outlook OST Viewer Software on your computer.
After launching the software click on Select OST button from menubar.
OST Viewer Software Main Screen
Step-2) Choose a file selection mode from the options, for adding OST files:-
  • Single File Conversion: - Select and add a single OST file from its known location.
  • Bulk File Conversion: - Choose this option to add multiple OST files at once
OST Viewer file selection mode
Step-3) Add OST files inside the software by selecting the needed option.
Browse & Select Outlook files

1) Click on "Select OST File" or "Search OST File" button and add an OST file into the software.
select pst/ost/nst
2) After adding OST files, click the "Start Scanning" button.
Search Outlook OST/PST & NST files from Drive

1) Click Add OST file or Add OST folder button to import multiple OST files into the software at one time.
select or add ost/nst/pst files in bulk
2) Add all required OST files, then hit the "Start Scanning" button for loading all OST file's inner data into the software.
Step-4) Scan OST files and extract all its inner folders and items into the software.
extract outlook folders from ost
Step-5) Click on the inner mail folders of OST files and load their inner items and click on each OST file item and get its preview separately.
Double click on each OST file item and view them on a separate screen.
preview Outlook items with attachments from OST file

Convert/ Migrate OST files using Pro and Pro plus edition of OST Viewer tool by applying the steps shown below: -

Convert OST to PST, EML, EMLX, MSG, HTML, MHTML, MBOX, NSF, vCard, ICS, Thunderbird, Zimbra(TGZ): -
Step-6) For OST file conversion choose a file format from these options- PST, EML, EMLX, MSG, HTML, MHTML, MBOX, NSF, vCard, ICS, Thunderbird, Zimbra(TGZ).

    With Export option, apply other settings in the software: -

  • Mail Filtering:- Choose a start and end date to convert OST file with emails of a specific date range.
  • Naming Convention :- Select a naming convention format for providing a custom name to resultant files.
  • Saving Location:- Choose a location where you want to save resulted files after conversion.
conversion options
    Export options/ conversion formats:-
  • Export to PST:- Convert OST to PST and save data of each OST files to separate PST.
  • Single PST for all Mailbox:- Save data of all selected OST files to a single PST file.
  • Export to EML:- Export and save Emails of OST files to separate EML files
  • Export to EMLX:- Convert OST file's emails to Apple Mail compatible EMLX files.
  • Export to HTML:- Save OST file email to HTML files for opening them with web browsers.
  • Export to MBOX:- Export OST mail folders to MBOX files. (Save OST mail folder's items to single as well as separate MBOX files.)
  • Export to MHTML:- Save OST file email to MHTML files separately.
  • Export to vCard:- Export contact items from OST file to vCard files.
  • Export to ICS:- Save OST file's calendar items to ICS files.
  • Export to Zimbra:- Export all email items from selected mail folders of OST file to single Zimbra desktop TGZ files.
  • Export to Thunderbird:- Transfer selected mail folders of OST file to Thunderbird profile's default storage location.
Step-7) After all selections, hit the Convert button and begin the OST file conversion process.
OST file conversion process
Migrate OST files to Cloud mail apps by following the below mentioned steps: -
Step-6) Select the needed folders from OST files, then click on Import into cloud button and follow the below mentioned steps to export OST files to Gmail, Office365, Outlook.com, Yahoo and other IMAP based mail apps
ost files import to cloud
Migrate OST files to Office365 cloud: -
Step-5) Select OST required folders of OST files from preview panel and click on Import to Cloud >> Import OST to Office365 option.
ost to office365 button
Step-6) Input email address of your Office365 account and click on "Convert".

Enter Office365 email address and password in the next screen and login into the software with your Office365 account details

ost to Office365 login
Step-7) After login process completion, the software will auto-start the OST to Office365 migration process.
OST to Office365 migration
Apply the steps showing below to Migrate OST files to Gmail/G-suite account:-
Step-5) Select needed folders from OST files and click on Import to Cloud >> Import to Gmail/G-suite option.
OST to Gmail import option
Step-6) Input your Gmail/G-suite account email address and google third party app password, then click the "Athenticate login" button.

Note: - For Gmail account login create Google Third party app password.

Gmail account login
Step-7) Login with your Gmail/G-suite account and click on Import OST to Gmail button then start the OST to Gmail migration.
ost to Gmail migration
Transfer data from OST files to YahooMail Account:-
Step-5) Select mail folders from OST files and click on Import to Cloud >> Import OST to Yahoo button.
import to cloud options
Step-6) Add your Yahoo mail account email address, and third party app password and click the "Athenticate login" button.

Note: - Create Yahoo Third party app password for yahoo account login

Yahoo mail login
Step-7) Click the Import to Yahoo Account button, and start OST to YahooMail migration.
import OST to Yahoo mail
Export OST files to Outlook.com/Outlook Web account:-
Step-5) View OST file data and make selection of needed folder, then click on Import to Cloud >> Import OST to to Outlook.com button.
Import ost to Outlook.com option
Step-6) Enter Outlook.com account email address, and password, then click on "Convert".
Outlook.com login
Step-7) Login with your Outlook.com or Hotmail account into the software and begin the OST to Outlook.com or Hotmail migration.
Migrate ost to Outlook.com/Yahoo Mail
Import OST to IMAP mail accounts applying the steps shown below: -
Step-5) Press Import to Cloud button and choose Import OST to IMAP option from menubar.
ost to Cloud options
Step-6) Input IMAP account details including- email address, password, port, hostname and click on "Convert".
login to IMAP account
Step-7) Login with your IMAP account into the software and start OST to IMAP migration.
Migrate OST to IMAP Server