Individual items are stored and transferred in MSG format, whereas complete mailbox or folder information is stored in PST format for backup and transfer purposes. Both formats are only used in the Outlook email client. SysTools MSG to PST Converter is a robust program that can convert MSG files to PST format. This tool converts exclusive or multiple MSG files into a single PST file, making it easier to store and read your emails in Outlook. It preserves your emails' original structure and integrity, including attachments, information, and formatting.