If you have Mac OLM files in bulk and you are looking for a solution to export them all at once then you can simply go with KDETools Mac OLM to Gmail Converter. The software has special features such as the batch convert option that allows users to select a large number of OLM records. It is compatible with all versions of Outlook like 2019, 2016, 2013, 2010, 2007, 2003 and many more.