best ask Microsoft that one. Or purchase one of the many Mbox to PST converters for sale on the internet.

Thanks for you reply, but the MS helpdesk also said to me the same. Due that I post this answer in Mozilla help. Which converters would you recommend more?

I really have no idea. I use Thunderbird. The last time I installed a Microsoft Outlook it never even started before it broke. The mail that used to be in it is probably still there, as it does not run.