If the target/destination needs populated with entries before starting synchronization, perform an initial upload. Uploads can be performed from the Control Panel.

1. Go to the Classic Control Panel > Synchronization Tab.
2. Select the desired topology from the list of topologies on the left.
3. Select Configure next to the pipeline on the right.
4. Select the Apply component.
5. Select START next to Upload. Once the upload is finished, the synchronization components are automatically started.