When importing prospects from a CSV file, it is important to remember a few key facts about how Pardot works:
Prospect email addresses must be unique in Pardot if your account does not allow multiple prospects with the same email address. In order to prevent duplicate records, only one prospect per email address will be imported. It is simple to check your CSV file for duplicate email addresses — just sort by email address so you can easily spot duplicates. Often times, you may have several contacts from a company listed as firstname.lastname@example.org or a similar general address.
The first row in a CSV is reserved for headings and is ignored during the import. The first row of your file is displayed for mapping purposes only.
Only valid email addresses will be accepted by the system. Any email addresses containing HTML or invalid characters will not be imported. Take care to ensure that your CSV file is devoid of any extra HTML formatting.
Prospects already present in the system remain tied to their original campaign.
Often, you may import a CSV and tag it as a new campaign you've created. Then, when you go to look at your campaign, it may contain less prospects than you expected. Keep in mind that if prospects you import are already in the system, associated with a different campaign, they will remain in their original classification for ROI calculation.
In the rare case that you may want to override the campaign for existing prospects, you can select the option to Set this campaign for all prospects in Step 3 of the Import Prospects Wizard. Again, this is not recommended in most cases as maintaining the first touch point/campaign for a prospect is essential to a true ROI analysis. Keep in mind that Campaigns can also be reassigned manually or using automation rules if you decide you need to change the Campaign for select prospects.