If you want the simplest method to convert OLM files to ICS format, using a dedicated conversion utility can make the process much easier. OLM files store multiple mailbox items, including calendar events. Tools such as the SysInfo OLM Converter allow users to load the OLM file, select calendar items, and export them directly to ICS format. The process is straightforward and helps keep all event information intact. more: https://www.sysinfotools.com/blog/convert-olm-to-ics/