It is possible to migrate a Source mailbox into a single subfolder of a Destination mailbox, but contact and calendar folders will need to reside under the root contacts and calendar folders.
These folder mapping support options ensure the folders are created at the correct location. Replace "DestinationFolder" with the name of the folder you want to use at the Destination.
First:
FolderMapping="^(?!Calendar$|Calendar/|Contacts$|Contacts/)->DestinationFolder/"
Second:
FolderMapping="^((Calendar)([/]?)|(Contacts)([/]?))->$2$4/DestinationFolder$3$5"
The support options above both need to be added in the Advanced Options for your project or for individual mailboxes.
To add for a single mailbox, click on the pencil icon to the far right side of the email address that you wish to edit.
The folder mapping support options listed above must be added in the order shown. If they are not added in this order, some contents of the migrating mailbox may become invisible and inaccessible on the destination
Destination Language
The spelling of both 'Calendar' and 'Contacts' must also reflect the language of the folder name at the Destination mailbox, e.g., 'Calendar' will be 'Calendrier' in French and 'Contacts' will 'Contactpersonen' in Dutch.
G Suite (GMail API) Limitations
For ‘GSuite (Gmail API) to GSuite (Gmail API)’ migrations only:
If you want to map multiple source labels into a single label on the destination, then the parent destination label must be created before starting the migration.
Example: If you wish to map three Source labels ('ABC', 'PQR', and 'XYZ') into one parent label ('DestinationLabel') at destination then you must create the parent label ('DestinationLabel') at destination mailbox before running the migration.