MBOX files stored on a Dovecot-based IMAP server cannot be accessed directly in Microsoft Outlook, because Outlook does not support the MBOX file format. Outlook works with PST files, so a conversion step is mandatory.
While it is technically possible to convert MBOX files to EML and then import them into Outlook, this approach is impractical for real-world scenarios. It is time-consuming, difficult to manage, and not suitable when handling bulk mailboxes or large datasets, which is typically the case with server-level backups.
For this reason, an MBOX to PST conversion tool (such as BitRecover MBOX to PST Converter) is recommended. It supports bulk MBOX data, preserves folder structure and metadata, and allows selective migration based on criteria like date, sender, or subject. The process runs 100% offline, ensuring data security, and works on Windows, macOS, and Linux, making it suitable for both single and multi-mailbox migrations.