How to import OLM calendar to Office 365 on Mac machine? Download and install OLM Converter for Mac Software and quickly import OLM calendar to Office 365 on Mac OS without a single error. It allows users to batch import OLM calendar to Office 365 on Mac OS with complete details. The Mac OLM File Converter is the best solution for how to import OLM calendar to Office 365 on Mac. Without losing single information, the program can easily convert multiple OLM files to O365 account at a time. Use the freeware edition and convert the first 25 items from each folder free of cost.