You can easily convert Mac PST files using MacUncle PST to IMAP Converter. The tool supports Mac OS Machines.
Start MacUncle PST to IMAP Converter on your Mac Computer.
Select PST file using Add File(s) or Add Folder(s).
Select specific folder to import.
Select IMAP option from Select Saving Option
Enter the details of IMAP Account such as Email ID, password, IMAP Port no., IMAP Host no.
Mac PST to IMAP conversion process completed successfully, you can see the message of completion.