Many users export Office 365 mailbox data to MBOX when moving to Mozilla Thunderbird or another email client that supports the format. The migration process should preserve mailbox folders, attachments, email headers, and metadata while ensuring that no messages are skipped during the export. Manual methods may become difficult for large mailboxes because they require additional applications and often involve multiple steps. Choosing a dedicated backup solution can simplify the process and reduce the chances of data inconsistency. The SysInfo Office 365 Backup Tool allows users to export Office 365 emails directly to MBOX while maintaining the original folder hierarchy, attachments, timestamps, and email formatting. It supports selective mailbox backup, custom date filters, duplicate email removal, and batch processing for multiple user accounts. The software also provides options to export Office 365 mailbox data into PST, EML, MSG, PDF, HTML, and CSV formats, making it useful for backup, migration, and long-term archiving. Its ability to handle large mailboxes efficiently makes it a practical choice for both individual users and business environments.
Office 365 mailbox allows user to save mailbox in PST file format. But taking a backup manually, user go through a large process. A nontechnical user cannot follow the all steps carefully therefore we need a automated solution. MailsDaddy Office 365 backup tool is designed to transfer data from Office 365 mailbox to PST, EML, MSG and MBOX file format. The software manages internal and external folder hierarchy during the whole conversion. It also offers backup options for primary, in-place archive, shared and group mailbox. User can perform backup process for individual or enterprise level.
A straightforward way is to export the Office 365 mailbox directly in MBOX format, then use that file with Thunderbird. You can first select the required folders or narrow the backup by date instead of taking the entire mailbox.
On Windows, I have found Softaken Office 365 Backup Pro useful when MBOX is the required destination. It connects through OAuth 2.0, lets you preview mailbox folders, select the needed data and save emails as MBOX. The software also supports mailbox, user and date filters, which is handy when only part of an account needs to be moved.
Once the MBOX file is created, it can be imported into Thunderbird. The demo covers 10 items, so you can test the export first.
