I suggest specialized tools that convert MBOX to PST files with ease, such as the eSoftTools MBOX to PST Converter Tool. MBOX to PST Converter software is a common and secure solution for exporting data from a variety of email clients, including Apple Mail, Thunderbird, Entourage, Pocomail, and others. They've changed the feature that allows you to convert items selectively and folders from MBOX to PST Files. A free version is available of this software.
Read More:- MBOX to PST Converter
To import Thunderbird mail into Office 365, use the SysInspire Thunderbird to Outlook converter Tool. It can quickly convert Thunderbird MBOX files to Office 365 files without missing email formatting, bcc, cc, email headers, dates, or affection files. It will load a Thunderbird profile account that has been set up for the conversion automatically.
Read More:- Convert Thunderbird Mail to Outlook
I recommend SysInspire's MBOX to PST converter, which can convert MBOX files to PST format and supports 20 other email clients that support MBOX files, including Thunderbird, Eudora, Spicebird, Seamonkey, and others. Users can also export MBOX files to Office 365 and Live Exchange servers using Sysinspire MBOX converter. The tool is compatible with all versions of Groupwise and Outlook.
Read More:- https://www.sysinspire.com/mboxconverter/