Migration Monster allows the transfer of large items but it is possible they could fail due to limitations configured on the destination email server.

If the destination mail server has a limit of 20mb and you send a 30mb attachment it will fail to migrate the item and report this in the log.

Another possibility causing a large item to fail is the destination mail server closing the connection before the file transfer has completed or firewalls configured to close long sessions.

Any failures of this sort will be reported in the error logs and you have the option to retry errors by selecting the Retry Errors option from the Projects main page