The migration of your retention labels is supported when you migrate in Insane mode with your source and destination site collections in the same Office 365 tenant.
There are a few things to consider with this scenario:
- If you migrate a retention label after editing your retention policy in the source, the policy applied at the destination will be the current one.
- When migrating list items, the default retention label at the destination will be applied if the source item has no retention label.
- When migrating documents, the source label is always applied at the destination.
- When migrating list folders that have a retention label, a warning might come up that reads: Value does not fall within the expected range. This is a generic warning that should have no impact on your migration.
Note: When retention labels are migrated in Normal mode, the retention label must be manually applied at the destination. The date on the label will show as the migration date and the user will be the user account used to migrate. In this case, the retention policy will be applied from the migration date and not from the date the label was applied at the source. The user and date values are not directly visible in SharePoint, you will only see the name of the label. This can be problematic if you use the setting when it was labeled in your Retention policy.