Is there a file size limit?

There is no strict file size limit. However, very large files (over 500MB) may be limited by your device's available memory.

What are the advantages of MBX over OST?

MBX Mailbox offers simple email storage used by Eudora and early Outlook Express, while OST Offline Outlook is known for enables offline Outlook access to Exchange/O365 email. The best choice depends on your specific needs — compatibility, quality, or file size.

How does Xonvert compare to desktop software?

Xonvert offers comparable quality to desktop converters with the convenience of browser-based access. No installation, no updates, instant availability.

Is it safe to convert my OST files here?

Absolutely. Your files never leave your device — all processing happens in your browser using WebAssembly technology.

Is there an API for OST to MBX conversion?

Xonvert is a browser-based tool without a server API, since all processing happens client-side. For automated conversion, you can use Xonvert's PRO features or integrate the underlying open-source libraries directly.

Are my files uploaded to a server?

No. Zero files are transmitted anywhere. Xonvert processes everything using client-side JavaScript and WebAssembly. Your files stay on your machine.

Can I preview the MBX output before downloading?

Yes. Xonvert shows a preview of your converted file so you can verify the result before saving it to your device.

Convert OST to MBX

Fast, free, and secure OST to MBX conversion. No registration required.

ost

mbx

Fast, free, and secure OST to MBX conversion. No registration required.

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High Quality

Maintain maximum quality during conversion

Fast Processing

Convert files in seconds with our optimized engine

Secure & Private

Files automatically deleted after conversion

How to Convert OST to MBX

Upload OST File

Click the "Select File" button to upload your ost file from your device.

Start Conversion

Click the "Convert" button to instantly start converting to MBX.

Download MBX

Download your converted mbx file immediately after processing.

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