You can backup your Office 365 emails and save various formats using DRS Office 365 backup tool. It is a very reliable tool that can easily backup multiple emails or data in a single attempt and saves OST, PST, EML, and MSG formats. it is more reliable and successful software for all users. It is also provided a free demo version and downloads free first 50 items per folder.

As far as I know, the most preferred and recommended solution to take multiple mailboxes backup of Office 365 concurrently is using Shoviv Office 365 backup software. It is advanced software that leads to a better and safe way to take backup of Office 365 mailboxes into PST. This tool also plays a full-prof roll to restore Office 365 backup file if needed. It has a free trial version as well.

Try third party utility that can convert and export all mailboxes items from Office 365 server to local hard drive. I am suggesting you this Office 365 Backup software, this software will help you to take all emails backup from Office 365 to multiple file extensions like PST, EML, EMLX, MSG, HTML and MBOX. This software is very simple to operate and handle the process wisely. Refer:- https://www.softakensoftware.com/office-365-backup.html

The Office 365 Email Backup Tool might be the best Office 365 Backup option for you if you're seeking the best Office 365 Backup solution. Because it has a few simple, secure, and dependable backup capabilities for user mailboxes, archive mailboxes, and public folders, users may also filter backups and schedule incremental backups (regularly). Office 365 users may also use this tool to create and run several tasks at the same time.