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Easily convert your OST files online with no registration required. Convert your OST documents from Windows, Linux, or macOS. Simply drag and drop your file into the upload form, select the desired output format, and click the convert button. Once the conversion is complete, you can download your XLSB file.
Depending on the OST file's size and format, conversion may take a few moments, but most files convert quickly. With advanced features, you can convert password-protected documents and have the results sent to your email.
Convert your OST documents anytime, anywhere, on any device—including mobile. Use this conversion app online 24/7—free for basic conversions.
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.
XLSB is a binary file format used by Microsoft Excel to store spreadsheet data, offering a more compact and efficient alternative to XML-based formats like XLSX. It is primarily supported by Microsoft Excel and a few third-party tools, such as LibreOffice and Apache POI, though compatibility may vary. The format stores data in a compressed binary structure, enabling faster loading and saving times, and supports advanced Excel features like macros, charts, and complex formulas while maintaining smaller file sizes compared to XML-based formats.
You can also convert OST into many other file formats. Please see the complete list below.