If you have OLM files from Mac Outlook and want to convert them into a different file format. So, you can take help with OLM Converter Tool. With the help of this utility, you can easily convert Mac OLM files to Email Formats such as PST, EML, & MBOX Format, Document Formats like PDF, TXT, CSV, HTML & vCard, and Email Services & Clients. Also, this utility allows you to upload Mac OLM to Cloud applications: IMAP, Gmail, Office 365, etc.

I would like to suggest you, use this PST to MBOX Converter to convert PST to MBOX file format. With this utility, you can easily and fast import bulk PST files from Outlook into MBOX format from any email client such as Thunderbird, Entourage, Opera Mail, Apple Mail, etc. Also, this tool extracts multiple Email Items: Addresses, Phone Numbers, and Contact Photos from PST files.