To manually import MBOX files into Outlook, open Mozilla Thunderbird or another email client that supports the MBOX format. Import your MBOX files into the client using the import feature. Then, drag and drop the emails from Thunderbird into a local folder. Next, use a tool like the BLR MBOX Converter Tool to convert the local folder “MBOX files” into PST file. BLR tools make the process easier, ensuring a smooth and accurate conversion and allowing you to migrate your emails with little effort.