Try to recover manual solution first before using any third party tool or software. This is because for the manual solution is free, you do not have to pay for this solution. There is another excellent vMail OLM to PSTConverter tool also available in online to migrate your OLM file to PST format without any difficulty. This tool can export Mac file to various other files like PST, EML, MSG and MBOX without making any change, and supports in all major versions of Windows operating systems e.g. 98, NT, 2000, 2003, XP, Vista, 2008, Win 7, Win 8 and Win10.