Convert OST to EML: Export Thousands of Outlook Emails in Minutes
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Written By
Aradhya Jain -
Approved By
Shivam Rathore -
Updated on
July 10th, 2026 - Read Time
7 minutes
User Query: How can I convert an OST file to EML without losing emails, attachments, and folder structure? I have an Outlook OST file that I want to open in another email application that supports EML files. Is there a safe way to export OST to EML, especially if Outlook is unavailable or the OST file is orphaned?
Introduction: Microsoft Outlook stores mailbox data in an OST (Offline Storage Table) file. It allows users to work with their emails even without an internet connection. However, there are situations where you need to access those emails in another email client that does not support OST files. Many email applications, including Windows Mail, Mozilla Thunderbird (with import tools), Apple Mail, and others, support the EML file format. This blog explains the manual method and the professional DRS Softech OST File Converter to convert OST to EML.
How to Convert OST File to EML?
An OST file can be changed to EML with the help of the technique available as an option that requires manual efforts or the usage of advanced OST to EML Converter. The manual technique is convenient when a few emails are to be converted but the use of professional tools can help in carrying out the conversion in bulk without any loss in formatting, attachments, or other details.
Best Way to Convert Outlook OST to EML Manually
When an OST file is associated with an ongoing Outlook profile, it is possible to save EML files using the manual technique. However, this technique is only useful when saving a limited number of e-mails and the software must be installed in the system.
Drag and Drop Emails from Outlook
- First, open Microsoft Outlook and access your OST mailbox.
- Now, create a new folder on your desktop.
- Open the mailbox folder containing the emails.
- Select one or multiple emails.
- Drag and drop the selected emails into the desktop folder.
- Outlook will save each email as a separate .eml file.
Limitations of the Manual Method
- It works only with an active Outlook profile.
- Cannot convert orphaned or inaccessible OST files.
- This method is not suitable for thousands of emails.
- Does not support batch conversion.
- Manual selection makes the process time-consuming.
- Increases the risk of missing important emails.
- May not preserve the original folder hierarchy during export.
Professional Tool to Convert OST to EML without Outlook
If you have large or multiple OST files for conversion, use the reliable DRS Softech OST to EML Converter Software. This tool is designed to convert a single or multiple OST files at once with no data loss. It preserves the original email formatting, structure, and metadata during the entire process. Offer several advanced features, including Remove Duplicates, Date Filter, Custom Folder Name, and more. With its simple interface, every user can easily use it. No technical skill is required. Apart from that, you can convert OST to MSG, and other formats (File Formats and Email Clients).
Export OST to EML Step By Step
- Download and install the DRS Softech OST Converter Tool.
- Choose “Select Files” or “Select Folder” to add your OST files. Click Next.
- Then, you can preview and select the files to convert. Use Search and Advanced Search option. Press Next.
- Select EML as the Saving Format from the drop-down list.
- Lastly, apply advanced features and filters as needed. Click Start Export.
Is It Possible to Convert an Orphaned OST File?
Indeed, transforming an orphaned OST file is a possibility; however, this cannot be accomplished using only Microsoft Outlook. An orphaned OST is cut off from its original account and thus Microsoft Outlook cannot carry out the opening or exporting of the file. However, there is the option of using a third-party OST to EML Converter tool to directly scan the orphaned OST file. The process includes exporting emails, attachments, contacts, etc. from the orphaned OST to EML.
Migrate OST Emails to EML for Forensic Export
Legal professionals and forensic scientists often want emails in a format that can be checked easily, can be kept intact, and can be presented as evidence. Each EML file consists of one email along with its metadata and Internet headers.
Affordable One-Time License: Unlike many email conversion tools that require recurring subscriptions, the DRS Softech Converter is available with a one-time purchase. It enables individuals and businesses to convert OST files to EML without ongoing costs while enjoying all advanced conversion and export features.
When Should You Use an OST Converter?
- You need to export thousands of Outlook emails quickly.
- The OST file is orphaned or inaccessible.
- Multiple employee mailboxes need to be archived.
- Emails must be shared with users who don’t use Outlook.
- You need individual EML files for legal, audit, or compliance purposes.
- Your organization is migrating from Outlook to an email client that supports EML.
Conclusion
In this technical blog post, we explored the two different methods to convert OST to EML. The manual method is suitable to convert a small number of OST files. However, it has several limitations for large or multiple conversion. Therefore, its best to use the professional tool. It support batch conversion with multiple advanced features. You can also download the demo version of this tool to test its features and functions.
Frequently Asked Questions
Ans. If OST files is connected with Outlook profile, then you can use the manual method. It is suitable for small files. Use the professional DRS Softech OST to EML Converter for bulk conversion with 100% accuracy.
Ans. Yes. the DRS Softech OST Converter Tool preserves the internet email headers, formatting, structure, attachments, and metadata during the process.
Ans. Click on Attachments Handling and choose Export Attachments Separately (Saves all email attachments in a separate folder) or Exclude Attachments (Converts only the email content to Markdown and skips all attachments).
Ans. The DRS Softech OST Converter is a desktop-based application that processes your mailbox data locally on your computer. It does not upload your OST files to any server, ensuring your emails remain secure, private, and under your complete control throughout the conversion process.
Ans. Yes. EML files preserve individual email properties, including Internet headers, timestamps, sender and recipient details, and attachments. This makes them suitable for legal discovery, compliance audits, and long-term email archiving.
Ans. Administrators can use the Select Folder option to add multiple OST files and export them in a single operation. This batch conversion feature saves time and simplifies large-scale email migration projects.
Ans. Businesses should choose a tool that supports batch conversion, orphaned OST files, Internet header preservation, duplicate email removal, date filters, preview options, attachment handling, and maintains the original folder hierarchy.
Ans. The Remove Duplicates feature identifies and skips duplicate emails during conversion. This reduces storage usage, avoids redundant email copies, and keeps the exported EML files organized.
Ans. The Date Range Filter allows administrators to export emails from a specific time period instead of converting the entire mailbox. This speeds up the conversion process and is useful for audits, legal requests, and selective email migration.
