If the goal is to convert OLM files into a usable format, you can do it without opening the original mailbox in Outlook for Mac. A dedicated OLM converter can read the file and export emails with attachments to formats such as EML, EMLX, MSG, PDF or MBOX.
Simple Conversion Steps
Open the OLM Converter and browse the required OLM file.
Preview the mailboxes, folders, attachments, contacts,
calendars or other available data.
Select the required items or choose the complete mailbox.
Pick the desired output format and destination.
Start the export and verify the converted files.
I’ve found TrustVare OLM Converter useful when selective conversion, orphan OLM files or preservation of folder hierarchy and email metadata is important. Its demo version lets you convert 10 items from each folder before purchasing.
If you need the exact method for OLM to EML, EMLX, MSG, MBOX, or PDF, I can explain that specific conversion.