How to Recover Emails from an OST file

Outlook 2019, Outlook 2016, Outlook 2013, Outlook for Office 365

You can use the OST Viewer (pstwalker.exe) to open or export emails from an offline Outlook Data File (.ost). OST Viewer can access orphaned, corrupted, encrypted, and password protected .ost files. Supported command line switches: export emails from an .ost file to .msg or .eml files; find and recover 'hard deleted' and 'orphaned' items.

Microsoft Outlook works pretty well once you have it set up and running. However, Microsoft Outlook also has its fair share of problems, whether you’re running it as an installed version or within Office 365. There are quite a few errors that could have taken place:

The reason behind these errors in Outlook is corruption is detected in your offline Outlook Data File (.ost). According to the Microsoft official article, Microsoft recommend that you delete your offline Outlook Data File (.ost) and that you let Outlook redownload the information from the server that is running Exchange Server. But, don’t delete the .ost file, back up this files. You can delete them once redownload is complete.

If .ost file downloading fails, and you can't open your mailbox file or having synchronization issues, you will need a backup copy of your .ost file. Download OST Viewer (pstwalker.exe) recovery tool and start .ost file recovery.

How to recover data from ost file?

Close Microsoft Outlook and all other mail-enabled applications that may use your Outlook mailbox.

Step 1. Start PST Walker, select the location on your computer with .ost file and open file.

Step 2. Preview all your items including messages, contacts, appointments, tasks, notes, and journal entries. Select the email message that needs to be recovered, and click "File"->"Save As...". To select multiple email messages, press and hold the Ctrl key while clicking on the items.

Recover emails from an OST file

Step 3. To recover all emails from OST file, click "File"->"Export", choose "All items in this folder" and click "Ok".

PST Walker Export Options

Now you can find the extracted data from ost file in the specified folder. Which you can then use to convert into existing or a new pst file with MSG 2 PST or view, search, organize and print messages without Outlook using MSG Viewer.

Command line switches

Have a lot .ost files to repair, but process requires more manual intervention than you want? Automate it with command line switches.

pstwalker.exe [filename] [/E[:msg|umsg|eml] [/Name[:Id|EntryId|Subject]] [/PATH:dest folder] [/FullScan] [/HardDeleted] [/HardDeletedOnly]]

filename Specifies the files to open/process. A filename mask can be applied,
e.g. c:\source_folder\*.ost
/E Bulk extract messages to
msg - .msg file format
umsg - unicode .msg file format
eml - .eml(rfc 822) file format
/Name Naming style for the saved messages
Id - incremental Id
EntryId - PR_ENTRYID (unique message identifier)
Subject - message subject
/PATH Specifies destination folder for bulk extracted messages
/FullScan Extensive scan (to recover data from a damaged or a corrupted .pst, .ost files)
/HardDeleted Find 'hard deleted' and 'orphaned' items
/HardDeletedOnly Export only 'hard deleted' and 'orphaned' items

Updated on June 02, 2021

Facebook Email

See Also

How to use PST Walker

This guide explains how to open, find and extract emails from .pst files and .ost files with portable PST Viewer.

Convert OST to PST file

The best Exchange OST to PST email conversion tool to convert .ost to .pst file. Export .ost files to .pst files without connection to Exchange. Supports all Outlook and Exchange versions including 2013 version.

Search multiple .pst and .ost files without Outlook

Boolean search, Excel-like filtering, instant search. Supports any .pst and .ost files: corrupted, orpah, archive, password protected and encrypted files. Export search results to numerous formats.

How to recover emails in Outlook for Microsoft 365

Learn how to troubleshoot missing data or emails in Outlook for Microsoft 365, and the steps to recover them if possible. Recover deleted messages in a user's mailbox in Exchange Online.