Convert an Offline File (.ost) to a Personal File (.pst)

Last reviewed on January 30, 2014

outlookiconOftentimes, Microsoft Outlook users who are leaving their current employer want to take their mail, calendar, or contacts with them and do one of two things – delete the Microsoft Exchange account from their profile without realizing the Contacts are stored in the Exchange account or they take the OST file with them, not realizing it can only be opened using the account that created it.

If you no longer have access to the computer that was used to create the OST or you don’t have a restore point, you’ll need to use a tool to recover the contents of the OST. A list of these tools is below. Note that OST2PST is free but will only work with OST files created by Outlook 2002 and older. If you aren’t sure what version of Outlook you used, try it; an error means the OST is not the correct type.

If your company uses a group policy that blocks PST creation, your choices are limited to exporting calendar and contacts to CSV (or Excel, if you have Excel at home). If you don’t have many calendar or contacts, you can forward them to a personal address. If using Outlook 2007 or 2010, you can send your entire calendar as an iCal.

Note: Check company policies before taking home the contents of your mailbox.

Restore Exchange Account

If you deleted the Exchange account, you may be able to recover the account if your operating system supports system restore and you only recently deleted the account. If too much time has passed you are less likely to have a restore point available.

  1. Open the system restore application. In Vista it is at Start Menu, Programs, Accessories, System Tools.
    Or enter %systemroot%\system32\rstrui.exe in Start search field or Start menu, Run.
  2. Pick a date just before the profile was deleted.

When Windows restarts the account will be back and you can move or export the contents of the OST to a PST. Then either delete the account or run restore again to return to the point made before the restore.

Method 1: Archive

You can use Archive to move or copy many items to a PST – this method is best when you want to move almost everything in your mailbox. Note that you cannot archive Contacts. Set the AutoArchive default in Tools, Options, Other, AutoArchive and apply it to all folders. Then go to File, Archive and run it.

AutoArchiving uses the last modified date so you’ll need to use a low number when archiving recent items. If you use Outlook 2007 or Outlook 2010 you can force AutoArchive to use the Received Date. See Using Microsoft Outlook’s Autoarchive feature

If you use this method and also need the Contacts, you’ll need to move them to the new data file.

Method 2: Export to a PST

Although Export is not usually recommended, when converting an OST to a PST, Export is generally a quick and easy way to move all content from the OST to a PST or ven just the calendar and contacts. If your company blocks the creation of PST files, export to CSV or Excel format.

Method 3: Move the items to a new PST

Create a new PST in your profile and drag the folders you want to take with you to the PST. This method will preserve custom views and forms published to folder.

Dragging default folders, such as Inbox, Calendar, and Contacts, brings up a message that you can’t move default folders. The contents will be copied instead, with the folder named Inbox (1), Calendar (1), etc.

Method 4: Forward by E-mail

If you don’t have too many items you want to keep, you can email them to your personal email address. Select the item(s), right click and choose Forward. If you have many, you could drag them to a folder in My Documents, then zip the folder and email the zip file.

Outlook 2007 or Outlook 2010 users can email the entire calendar as a single iCal, provided they use Outlook 2007 or another calendaring application that supports multi-event icals at home. Older versions of Outlook do not support multi-event icals.

Tools in the Spotlight

DataNumen Exchange Recovery

DataNumen Exchange Recovery repairs and recovers corrupted Microsoft Exchange offline storage (.ost) files. Exchange Recovery can scan orphaned OST files and recover mail messages and other items, including folders, posts, appointments, meeting requests, contacts, distribution lists, tasks, journals and notes. The recovered items are saved in PST format readable by Outlook, Other important features: recover attachments and deleted items, recover oversized 2GB OST files, support to convert OST files into PST files.

Stellar OST to PST converter

Stellar OST recovery software is the most efficient tool to convert Outlook OST file to PST file. The software successfully recovers all the components of .ost file such as emails, contacts calendar entries, attachments etc. The tool is able to convert OST file to working PST file in any instance of corruption. Free demo version is also available that previews all recoverable items of inaccessible .ost file.

Tools - Convert OST to PST service

This is an alternative way to convert OST file to PST. If you don't want to buy specialized software you should use service. You don't need any special knowledge. Just send the order for converting. You'll receive detailed instruction and after 8-24 hours you'll receive PST file which can be opened by Outlook. All types of data from OST (emails with attachments, calendar, contacts, tasks, notes) will be available in PST file.

Kernel OST Viewer

Kernel OST Viewer is a FREE utility to view the contents of OST files. It does not require Outlook installation. A connection with Exchange is also not required. Just select the OST file and it will mount it in its Outlook like GUI instantly.

OST2 PST Converter

OST2 PST Converter allows you to convert connected Microsoft Exchange .OST files to Outlook .PST files. Convert files in a couple of clicks - select an OST file and choose the location where you want to save the PST file. OST2 will automatically connect the converted files to Outlook, so you won't need to import .pst files manually. The free version converts OST files in Outlook profiles; orphaned OST files that are not connected to Outlook profiles can be converted to PST format using OST2 Enterprise Edition.


Free tool to convert older *.OST files to *.PST files. Works with ANSI format only, will not work with OST created by Outlook 2003/2007.

PST Merger

Merge PST files with free software for Microsoft Outlook that combines PST files into a single PST file. Merge selected folders from PST files, such as, Inboxes, Calendars, Contacts, Journals, Tasks etc. to another PST file. All your data stored in original PST files will be preserved and merged without making any changes to the original files. For more flexible PST merging options use PST Merger Pro Edition. Merge, move or copy specified Microsoft Outlook folders from unlimited PST files at once. Move or copy specified Outlook data from one PST file to a selected PST file without the need to merge all content from both PST files.

RecoveryFIX for OST Recovery

Exchange OST to PST email conversion tool to convert OST file to PST file. Convert working or unusable OST file to into PST file. Use it to migrates all Outlook items from Exchange Offline Storage (.OST) file to Personal Storage File (.PST). Software converts and repairs the offline storage file (ost) to personal storage (pst) file so that it can be easily accessed with Outlook. Other saving options include .EML and .MSG where former is accessible with Outlook Express and latter with Outlook. If the ost file gets corrupt or damaged, OST to PST functions as ost recovery software.

Written by

Diane Poremsky
A Microsoft Outlook Most Valuable Professional (MVP) since 1999, Diane is the author of several books, including Outlook 2013 Absolute Beginners Book. She also created video training CDs and online training classes for Microsoft Outlook. You can find her helping people online in Outlook Forums as well as in the Microsoft Answers and TechNet forums.

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