There are several options available to import bulk MBOX files to Office 365 in a single process. One such option is the SameTools Cloud Importer Tool. This automation process is the best way to import MBOX files to Office 365 in a single process, thanks to its incredible functionality and built-in risk-free technology against viruses and malware. Once a user uploads MBOX files, the utility begins scanning all MBOX file data. It easily import MBOX files into Office 365 in a single time processing. The utility is based on advanced technology and has built-in risk-free technology against viruses and malware.