Prepare a permission-based list
Export only contacts you are allowed to email. Keep consent evidence and existing unsubscribe or suppression records. Never treat a purchased list or an old customer list as automatic marketing permission.
Review before importing
Open the audience import flow, provide your CSV and inspect the review before applying it. Check email addresses, names, tags and consent information. Start with a small synthetic sample on staging.
Protect existing preferences
Do not change suppressed or unsubscribed contacts into active subscribers. Compare sample records after the import and run an audience rehearsal before any campaign.
Keep an exit path
Export the local audience when needed and use the privacy tools to handle appropriate access and erasure requests. Store exports securely; they can contain personal information.