Not long ago, I had the same issue when I needed to import many MBOX files from Thunderbird and Apple Mail into Outlook on my Windows PC. DataVare MBOX to PST Converter was the most reliable and worked the best of all the apps I tried.
This tool was great because it let me turn many files at once, instead of having to do them one by one.
When I used big MBOX files, it worked great and kept the folder organization, email formatting, attachments, and metadata. It doesn't matter if your MBOX files came from Thunderbird, Apple Mail, or somewhere else; it will handle them without any problems.
Another great thing about it is that you don't have to install Outlook to use it, and you can try it out with a few emails before you buy it. MBOX to PST Converter is a great tool to import MBOX into Outlook that is both reliable and easy to use.
