Manual

60 Google Apps Migration with IMAP Connector Administration Guide
Contacts
When migrating contacts, if you remigrate and choose “Migrate all data (overwriting
previously migrated data)” duplicate contacts will be created in Google Apps. If this
occurs, the user can use the “Find Duplicates” option in Google Apps contacts to merge
duplicate contacts.
The contact migration tool will migrate new contacts created since your last migration, but
does not migrate contacts that have been modified since the last migration.