The vMail Mac OLM to PST Converter tool is very convenient software for importing your files without any doubt and any error. The software can export any size of data without any loss. You can export only selected files and install at the desired location. The easily runs on Mac 10.10, 10.11, 10.12, 10.13. Being a daily migrator, I know the solution will work on your problem.

Get more info- https://www.vsoftware.org/blog/import-outlook-olm-into-mac-mail.html