How do Delta migrations work?
The following are technical details about Delta migrations.
MigrationWiz was designed to never duplicate items that have been migrated by the service itself. No matter how many times you submit a migration, you should not encounter duplicates. For more details, click here.
MigrationWiz does not delete items during Delta migration passes. For example, consider a contact which was migrated during a first pass, and later deleted at the Source. No deletion will be made to the Destination during a Delta migration pass.
MigrationWiz does not update items during Delta migration passes: only items not migrated during previous migration passes will be migrated. For example, consider a contact which was migrated during a first pass and later modified at the Source. No update will be made to the Destination during a Delta migration pass. However, Advanced Options can be used to override this behavior. (See KB005290: "What do I need to know about the Sync Migration Pass?" for a list of supported options.)
- You can perform a Delta migration pass by selecting the same mailbox in MigrationWiz, and then clicking on the Start button, followed by selecting the option for Full Migration.
- It is possible to specify folder, date and item type filters when performing Delta migration passes. However, in most cases, this is not required because MigrationWiz automatically finds items which haven't yet been migrated.
- Suppose that items in Source Folder A were migrated, and then later moved to Source Folder B. MigrationWiz remembers which items it migrated from Folder A. However, because items have been moved to a new Source Folder B, these items will be remigrated to Destination Folder B.