How to Convert Outlook to MBOX file format?

If you want to convert Outlook data in MBOX format then first you need to configure Outlook to Gmail using IMAP protocol and then use Google takeout to export data in MBOX format.

 

Note: Do with new gmail id or first manage the data in a particular tag then take a backup of Gmail according to lable. 

 

On other hand you can use any third party tool. 

 

I hope, it will be helpful for you.