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OST Recovery and Migration

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  • Connect to Exchange server for multiple mailboxes migration
    • Connect with Global Admin
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    • Connect with Full Access permissions
    • Using multiple user credentials with CSV file
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    • Exchange 2007 and below
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  • Knowledge Base
    • Corrupt OST file recovery
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    • Errors have been detected in the OST
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  2. OST Recovery and Migration
  3. How to Convert OST to PST in Outlook 2024, 2021, 2019, 2016 and Earlier | EdbMails
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How to Convert OST to PST: Step-by-Step Guide for All Outlook Versions

An OST file is Outlook's local offline copy of your Exchange or Microsoft 365 mailbox. It is what lets you keep working when you are not connected to the server: emails, contacts, calendars, all of it stays accessible. The catch is that it is tied to the account and profile that created it. You cannot copy it to a new machine and just open it in another Outlook profile. You cannot access it after the Exchange account is deleted. And if it gets corrupted or orphaned, Outlook simply will not touch it.

Extracting data from an OST file, particularly one created by an older version of MS Outlook, can pose challenges. Converting the OST to PST breaks that dependency. A PST file is standalone. It opens in any Outlook profile on any Windows machine, with no server or account required. That is why OST to PST conversion comes up in so many situations: moving to a new computer, recovering data after an Exchange server failure, creating an offline backup, or dealing with a corrupted OST that Outlook refuses to open.

Convert OST to PST from all Outlook versions

There are three ways to do it. The first two are built into Outlook and work fine when your OST file is healthy and still tied to an active profile. The third option is EdbMails OST to PST converter, which is what you reach for when the built-in methods fail.

MethodWorks on corrupted OST?Works on orphaned OST?Requires Exchange connection?Best for
Import/Export WizardNoNoYesHealthy OST, full mailbox export
Auto ArchiveNoNoYesArchiving older items by date
EdbMailsYesYesNoHealthy, corrupted, orphaned, encrypted, or any sized OST files

Reasons to Convert OST to PST Format

There are several compelling reasons to convert OST files to PST format:

  • When migrating mailbox data from one system to another, relying solely on the OST file can be complex. Converting OST to PST streamlines the migration process, ensuring a smoother transition.
  • Large OST files are prone to corruption and damage, putting your data at risk. By converting OST to PST, you can mitigate the chances of data loss and overcome mailbox size limitations.
  • In cases where the Exchange Server encounters problems or if Exchange data is accidentally deleted, having previously converted OST files to PST format provides a reliable way to maintain access to your valuable mailbox items.
  • OST to PST conversion allows you to conveniently access and manage your offline-saved OST file data in Outlook's PST format. This enables seamless online access to your mailbox items.
  • OST files are compatible only with Exchange and Outlook. If you plan to switch to a different email client, converting OST to PST becomes essential for migrating your old mailbox items to the new platform.
  1. Methods to convert OST to PST

    If you need to convert an OST file to PST format, it is important to proceed with caution. Before you get started, ensure that your Outlook account is synced with the Exchange profile and that you have the necessary login credentials. Additionally, take a backup of your mailbox data and store it securely, as manual methods may carry some risks.

    • Method 1: Convert OST to PST Using the Outlook Import/Export Wizard

      Outlook's Import/Export wizard is the most straightforward route when your OST file is healthy and still connected to an active Exchange or Microsoft 365 profile. It works across all Outlook versions, though the menu path changed slightly between older and newer versions, use the steps below that match what you are running.

      One thing to check before you start: if you are on Outlook 2016 or later and your account uses Cached Exchange Mode, Outlook may only export the last 12 months of mail by default. If you need your full history, go to File > Account Settings > Account Settings, double-click your Exchange account, and drag the Mail to keep offline slider to All before running the export. It is a step that is easy to miss and explains why many users end up with a PST that looks incomplete.

      • Step 1: Open the Outlook Import/Export Wizard

        • Launch Microsoft Outlook and click the File tab on the top left corner of the window
        • Navigate to Open & Export and select Import/Export

          import and Export

      • Step 2: Select the Export Type and Save Location

        • From the Import/Export wizard, choose Export to a file and click Next
        • Select the file type as Outlook Data File (.pst) and click Next
        • Choose the folder or account that you wish to export and click Next
        • Select a location to save the exported PST file and give it a name

          outlook data file

      • Step 3: Pick the Mailbox Items to Export

        • Select the Include subfolders option to export all items in the folder, if you skip this, only the top-level folder comes across, not the subfolders inside it
        • If you wish to export only specific items, choose Filter and set your criteria
        • Click Next to proceed

          select-the-folder

      • Step 4: Export the OST File to PST

        • If you want to protect the exported PST file with a password, enter it and click OK
        • Click Finish to start the export
        • Allow the process to complete, then click OK to acknowledge
      • Step 5: Import the PST File into Outlook

        Once the export is done, here is how to bring the PST back into Outlook:

        • Open Microsoft Outlook and click the File tab
        • Click Open & Export and choose Import/Export
        • Select Import from another program or file and click Next
        • Choose Outlook Data File (.pst) as the file type and click Next
        • Browse to where you saved the PST file and select it
        • To prevent duplicates, choose Replace duplicates with items imported
        • Select the folder or account where you want the data and click Finish

        For Outlook 2013 and 2010: The menu path is the same, File > Open & Export > Import/Export. If you cannot see "Open & Export," go to File > Open > Import and follow the same steps from Step 2.

        For Outlook 2007: Go to File > Import and Export and follow the same steps from Step 2.

        What to do if the export completes but the PST is missing items: This almost always means Outlook is only exporting its cached data, not your full mailbox history. Go back to your account settings and change the sync window to All, then re-run the export. If the OST file itself is damaged or disconnected from Exchange, the sync window change will not help, move to Method 3.

    • Method 2: Convert OST to PST Using Auto Archive Settings

      Auto Archive is less of a full conversion tool and more of an ongoing housekeeping feature. It moves older items out of your live mailbox into a PST file on a schedule you define. It is useful if your goal is to reduce mailbox size or archive emails older than a certain date rather than export everything at once.

      It is not a substitute for a full OST to PST conversion, and it will not help if your OST file is inaccessible or disconnected from Exchange. But if you are on a healthy mailbox and want to archive older items automatically, here is how to set it up.

      One heads-up before you start: Auto Archive skips Contacts by default, and it will not run until the time interval you set has passed. If you need the archive right now, use the manually trigger the archive process described at the end of this section rather than waiting for the schedule.

      • Step 1: Access Auto Archive Settings in Outlook

        Launch Microsoft Outlook and click the File tab

        Navigate to Options > Advanced > AutoArchive Settings

        AutoArchive Settings

      • Step 2: Configure Auto Archive Options

        • In the Auto Archive settings window, check Run AutoArchive every and specify the frequency
        • Choose the folder(s) you wish to archive
        • Set the age threshold, items older than this will be moved to the archive
        • Designate the location where you want to save the archived PST file
        • Click OK to save
      • Step 3: Customize Auto Archive for Specific Folders

        If you want different archive settings per folder:

        • Right-click the folder in Outlook's navigation pane
        • Choose Properties
        • Go to the AutoArchive tab
        • Select Archive this folder using these settings and configure your preferences
        • Click OK
      • Step 4: Initiate the Archive Process

        • Allow the time frame you configured to pass for the process to run automatically, or
        • Manually trigger the archive process by clicking File > Tools > Clean Up Old Items in Outlook 2016 and later, or File > Cleanup Tools > Archive in Outlook 2013/2010
        • Check the designated save location to confirm the archived PST file was created

        Note: If your OST file is corrupted or orphaned, direct export or archiving from Outlook may not be possible. In such cases, you can use EdbMails to repair corrupt OST files and convert them to PST format.

      Challenges of Exporting OST to PST from Outlook

      1. Lack of Support for Older Versions: Older versions of Outlook no longer receive security updates, feature enhancements, and patches. This lack of support can hinder the smooth exporting of OST files to PST.
      2. Data Integrity and Compatibility Concerns: When converting OST files to PST from older Outlook versions, compatibility issues can arise, particularly around special characters, oversized OST files, metadata, and calendar items. These can impact data integrity during conversion.
      3. Complex Manual Export Process: Manually exporting OST to PST requires a good understanding of Outlook's export wizard and in some cases scripting knowledge. The process can be time-consuming and error-prone, especially without technical experience.
      4. Difficulty Diagnosing Errors: Older Outlook versions lack comprehensive error reporting, making it harder to diagnose and fix conversion errors. This leads to frustration and delays.
      5. Performance and Stability: Older versions of Outlook can exhibit sluggish performance and frequent crashes, which further complicates OST to PST exports.

      To avoid these challenges, using a reliable third-party tool like EdbMails is the practical solution.

    • Method 3: Convert OST to PST Using EdbMails

      When converting an OST file to PST using Outlook's built-in tools is not working, because the OST is corrupted, the Exchange account no longer exists, or you are working on a different machine, EdbMails handles the conversion without needing the original Exchange profile or a live server connection.

      With EdbMails, you can easily convert your OST files to PST, allowing seamless access to your emails, contacts, calendar entries, and other mailbox data across any version of Outlook. You can also apply filters to export selective mail items based on date, subject, sender, or attachment criteria. Exporting special characters and metadata is handled automatically.

      For the full walkthrough with screenshots, advanced options, and feature details, see the EdbMails OST to PST Converter.

      To convert OST to PST using EdbMails, follow the steps below:

      • Step 1: Download and install EdbMails OST to PST Converter tool
      • Step 2: Choose the OST file from any Outlook version
      • Step 3: Select the mail items and folders for PST conversion
      • Step 4: Convert the Outlook OST file to PST format

Video Tutorial to Convert OST to PST :

  • OST to PST converter video

Supported Outlook versions: 2024, Microsoft 365, 2021, 2019, 2016, 2013, 2010, 2007, 2003

Supported Exchange versions: 2007, 2010, 2013, 2016, 2019, Exchange Online

When the Manual Methods Fail: Common Scenarios and What to Do

"Outlook cannot open the OST file" The OST file is orphaned or the Exchange account it was linked to has been deleted. Outlook cannot open an OST that is no longer connected to its original account. There is no workaround using Outlook's native tools. Use EdbMails, which reads orphaned OST files directly without needing the original account or server.

"The export completes but the PST is empty or missing items" Outlook's Cached Exchange Mode sync window is almost certainly the cause. Outlook 2016 and later default to caching only 12 months of mail, so the export only captures the cache, not the full mailbox. Change the Mail to keep offline slider to All in your account settings before re-running the export. If the OST is damaged, this will not help, use EdbMails instead.

"SCANPST says the file is too damaged to repair" SCANPST is designed for minor corruption only. It frequently fails on heavily damaged, oversized, or ransomware-affected OST files. EdbMails handles cases that SCANPST cannot, extracting whatever data is recoverable and converting it to PST. See also: Repair corrupted OST files from Outlook 365.

"I'm on a new computer and don't have the original Outlook profile" The Import/Export method requires the original Outlook profile to be present. Without it, Outlook cannot open the OST. EdbMails converts OST files independently, just point it at the file and run the conversion.

"My OST file is encrypted or password-protected" Outlook's Export wizard cannot handle encrypted OST files from certain Exchange configurations. EdbMails supports conversion of encrypted OST files without compromising data integrity.

"Outlook shows 'The set of folders cannot be opened'" This is a common error when the OST file has become inaccessible. See Fix Outlook the set of folders cannot be opened for the full troubleshooting guide.

Version and Scenario Support Reference

Outlook VersionImport/Export MethodAuto Archive MethodEdbMails
Outlook 2024 / Microsoft 365✓✓✓
Outlook 2021✓✓✓
Outlook 2019✓✓✓
Outlook 2016✓✓✓
Outlook 2013✓✓✓
Outlook 2010✓✓✓
Outlook 2007✓(different menu path)✓✓
Outlook 2003LimitedLimited✓
Corrupted OST✗✗✓
Orphaned OST✗✗✓
Encrypted OST✗✗✓
Large OST (10 GB+)✓(slow)✗✓
No Exchange connection✗✗✓

Benefits Of EdbMails OST to PST converter tool

EdbMails recovers all your valuable data from OST files and converts them into PST format. Let's explore the benefits and features of EdbMails OST to PST converter:

  1. Simple and User-Friendly: EdbMails provides a user-friendly interface that makes the recovery and conversion process a breeze. Even users with limited technical expertise can easily navigate the software and perform OST to PST conversion without any hassle.
  2. Comprehensive OST Recovery: EdbMails ensures a thorough recovery of all mailbox items including emails, contacts, calendars, tasks, notes, journals, and more from OST files. This means that no matter what data is stored in your OST files, EdbMails will retrieve it all for you.
  3. Accurate Conversion: When it comes to converting OST files to PST, data integrity is of utmost importance. EdbMails preserves the original folder hierarchy, email properties, and attachments during the conversion process. This ensures that your converted PST files are an exact replica of your original OST files.
  4. Selective Conversion: EdbMails provides the flexibility to choose specific items or folders for conversion. This allows you to save time and disk space by excluding unnecessary data from the conversion process.
  5. Preview and Filter: With EdbMails, you can preview the recoverable items from OST files before initiating the conversion. Additionally, advanced filtering options are available to refine the recovery process based on criteria such as date, subject, sender, and more.
  6. Split Large OST into smaller PST Files: Large PST files can cause performance issues in Outlook. EdbMails enables you to split oversized PST files into smaller, manageable sizes during the conversion process. This ensures optimal performance and avoids any potential data corruption.
  7. Compatibility and Support: EdbMails OST to PST converter supports all versions of Outlook, including Outlook 2019, 2016, 2013, and earlier. It is also compatible with various Windows operating systems. In case of any queries or issues, EdbMails provides 24/7 technical support to assist you.

Frequently Asked Questions

  1. How do I convert an OST file to PST?

    The quickest way is through Outlook's own Import/Export wizard, go to File > Open & Export > Import/Export, choose Export to a file, pick Outlook Data File (.pst), select the mailbox or folders you want, choose where to save it, and click Finish. That covers most straightforward situations. Where it falls apart is when the OST file is corrupted, orphaned, or no longer tied to an active Exchange account, in those cases Outlook either refuses to open the file or exports an incomplete result. That is where EdbMails comes in: it reads the OST file directly without needing the original profile or a live server connection.

  2. Can I convert a corrupted OST file to PST?

    Not with Outlook's built-in tools, they only work with a healthy, accessible OST file. If you have tried SCANPST and it either could not repair the file or kept failing partway through, that is a sign the damage is beyond what Microsoft's own tool handles. EdbMails is built specifically for this situation: it pulls data out of corrupted, encrypted, and even ransomware-affected OST files and converts them to PST without needing the original Exchange account or a working Outlook profile.

  3. How do I convert an OST file to PST in Outlook 2016?

    In Outlook 2016 go to File > Open & Export > Import/Export. Choose Export to a file, then Outlook Data File (.pst), and select the mailbox or folder you want to export. Make sure you tick Include subfolders, if you skip this, only the top-level folder comes across. Pick a save location and click Finish. One thing to watch: if your account uses Cached Exchange Mode with a limited sync window, you will only get the cached items, not your full mail history. Change the Mail to keep offline slider to All in your account settings before running the export if you need everything.

  4. How do I convert an orphaned OST file to PST?

    An orphaned OST is one that has been cut off from the Exchange account it belonged to, the account was deleted, you have moved to a new machine, or the Exchange server is gone. Outlook simply will not open it. There is no workaround using Outlook's native tools. EdbMails handles orphaned OST files directly, it does not need the original account, profile, or server connection. You point it at the file, it scans and loads the data, and you export to PST from there.

  5. Does converting OST to PST delete the original OST file?

    No, nothing touches the original file. Both the Outlook Import/Export method and EdbMails are read-only operations on the source OST. Your original file stays exactly where it is, unchanged. It is safe to keep a copy of the OST as a backup even after a successful conversion.

  6. What is the difference between an OST file and a PST file?

    An OST file is Outlook's local cache of your Exchange or Microsoft 365 mailbox. It is locked to the account and profile that created it, you cannot copy it to another machine and open it directly. A PST file is a standalone data file you can open in any Outlook profile on any Windows machine with no server or account dependency. That portability is the main reason people convert OST to PST. For more on Outlook Cached Exchange Mode and how it affects your OST file, see the linked guide.

  7. Why is my exported PST file missing emails?

    The most common reason is Outlook's Cached Exchange Mode sync window. Outlook 2016 and later default to syncing only 12 months of mail, so when you export, only those 12 months come across. To fix it, go to File > Account Settings > Account Settings, double-click your account, drag the Mail to keep offline slider to All, and re-run the export. If the OST file itself is damaged, EdbMails can recover the full mailbox.

  8. Why can't I open my OST file directly in Outlook?

    OST files are not directly openable as standalone files, they are tied to the Exchange or Microsoft 365 account that created them. If you see errors have been detected in the OST or Outlook is not syncing correctly, the OST file may need to be repaired or rebuilt before you can export its contents. If Outlook refuses to open it at all, converting to PST using EdbMails is the most reliable path forward.


Additional resources:

  • Repair Corrupt OST File
  • Free OST File Viewer
  • Recover Orphaned OST File
  • Import OST File into Outlook
  • Rebuild OST File
  • OST to Office 365 Migration
  • OST to Exchange Migration
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IntroductionReasons to Convert OST fileOST to PST Export MethodsVersion and Scenario SupportBenefits of EdbMails OST ToolFAQs

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