This method applies to SmarterMail 8.x - 12.x:

Follow these steps to import messages into SmarterMail from .EML files:

Stop the SmarterMail service.

Delete the mailbox.cfg file in the folder that the *.EML files will be imported into.

Copy the *.EML files into that folder.

Start the SmarterMail service.

The emails will be converted into .GRP files once the user accesses their mailbox, either via webmail or using an email client, for the first time after the EML files are copied over.

NOTE: If you delete the mailbox.cfg file out of a folder that already had GRP files, all timestamps will be reset to midnight for the emails that are already contained in those GRP files. That date will remain the same.