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Convert OST files online instantly, no sign-up required. You can convert your OST documents on any platform—Windows, Linux, or macOS. Upload your file, choose the output format, and press convert. When the process is done, your EML file will be ready for download.
The OST file's size and structure affect conversion time, though most files are processed in seconds. Advanced features allow you to convert password-protected documents and receive conversion results via email.
No matter where you are, convert your OST documents seamlessly on any device, including smartphones. Available online anytime, this conversion app is completely free for basic scenarios.
Check our videoAn OST (Outlook Offline Data File) is a file format used by Microsoft Outlook to store a synchronized copy of mailbox data locally, enabling offline access to emails, calendars, contacts, and other items. It is primarily used by Microsoft Outlook and can be accessed or converted using tools like Kernel OST to PST Converter, Stellar Converter for OST, and SysTools OST Viewer. The OST file structure is based on the Messaging Application Programming Interface (MAPI) and supports advanced features like synchronization with Exchange Server, encryption, and data compression for efficient storage and security.
The EML file format is a standard for storing email messages, widely used for archiving and sharing emails across different platforms. It is supported by various email clients like Microsoft Outlook, Mozilla Thunderbird, and Apple Mail, as well as web-based tools and email servers. The format is plain text-based, typically encoded in MIME (Multipurpose Internet Mail Extensions), allowing it to store email content, attachments, headers, and metadata in a structured and interoperable manner.
You can also convert OST into many other file formats. Please see the complete list below.