How does Mailshake handle duplicates?

When you're adding prospects to a campaign, if the prospect already existing in that same campaign, Mailshake won't let you add those prospects to a campaign. You'll see that those prospects weren't included.

When you upload your prospects to the campaign you'll also be shown if some of your prospects are in a previous campaign in the Review Prospects step.  At that time, you'll be able to Remove them or ignore the notice and continue adding them to the campaign. Mailshake will default to adding prospects to a campaign if they exist in a different campaign so we recommend waiting for the import to process and for the Review Prospects section to appear.