How to EXPORT emails & contacts from Outlook for Mac to a USB disk so that it could be archived or used in PC for Windows?

I would like to Export all emails and contacts from my Outlook for Mac to a USB drive so that it can be used in PC for Windows. I tried following the steps in Outlook, i.e. Export...to .olm files but I get faiure messages plus need to rebuild the Database using MS Database Utility. When I follow this instruction, after several hours it gives a message that the database cannot be rebuilt. I have important work related emails since 2003 which needs to be kept and transfered to my successor.