The best and most secure tool to backup Office 365 mailbox is the MailConverterTools Office 365 Backup Tool. It is the complete solution to backup & restore the entire Office 365 mailbox. This software provides various exclusive features and a simple interface for a better user experience. It has a date filter that enables users to perform selective migration of Office 365 emails based on dates. This software simplifies the migration of emails from Office 365 to Gmail, AOL, IMAP, and other email providers. Plus, it can backup Office 365 contacts, calendars, journals, etc along with emails without hampering the original data structure. Furthermore, this tool can export Office 365 to MBOX, PST, PDF, EML, CSV, and other formats without any error.

Shoviv Office 365 Backup Tool is a comprehensive utility designed to securely back up Office 365 mailboxes into various formats such as, PST, OLM, MBOX, and EML. This tool is known to have a simple GUI and high compatibility, where users can set the backup operations to run at their specified time. Some of these are incremental backups that help to avoid exporting data repeatedly; and filter options for backup according to date and specific folders. Their usage is particularly crucial for industries, such as finance and healthcare; data protection legislation are effective with the backup of data integrity and accessibility during technical problems.

Read also - Backup Microsoft 365 Mailboxes

The best Office 365 Email Backup software is Aryson Office 365 Email Backup Software which take the backup of 365 account data in multiple file formats such as PST, EML, MSG, MBOX, and many more. The tool migrates Office 365 data to Gmail, Thunderbird, Yahoo Mail, iCloud, and other email clients. Additionally, it removes duplicates from the selected folders before the backing process and provides feature to view the selected files in Advance Preview Panel. Along with that, the tool supports all Windows OS and has an easy-to-use user interface.

If you're looking for a reliable Office 365 email backup tool, I highly recommend Regain Office 365 Email Backup Tool. Here’s why:

1. Comprehensive Backup Options:
   The tool offers various backup options, allowing you to back up not just emails but also contacts, calendars, and attachments. This makes it a well-rounded solution for all Office 365 data.

2. User-Friendly Interface:
   The interface is intuitive, so even non-technical users can navigate and operate the tool easily. You don’t need extensive IT knowledge to back up your emails securely.

3. Multiple Export Formats:
   Regain Office 365 Email Backup Tool allows you to save your emails in multiple formats like PST, EML, MSG, MBOX, etc., which provides flexibility depending on your storage and retrieval needs.

4. Selective Backup Feature:
   One of the standout features is the selective backup option. You can choose specific folders, dates, or even individual emails to back up, saving time and storage.

5. Secure and Reliable:
   Data security is critical, and Regain's tool offers end-to-end encryption, ensuring that your backups remain secure during the entire process.

6. Automated Scheduling:
   Set up automatic backup schedules with ease, ensuring your data is always backed up without manual intervention. This feature is especially useful for businesses that want to maintain continuous backup without the hassle.

7. Cost-Effective:
   Compared to many competitors, the Regain Office 365 Email Backup Tool is more affordable, offering great value without compromising on essential features.

Final Thoughts:

Overall, the Regain Office 365 Email Backup Tool is an excellent choice for individuals and businesses alike who need a reliable, secure, and user-friendly solution to back up their Office 365 emails. I've used several tools, but this one stands out for its ease of use and comprehensive feature set.