If a registrant gets two confirmation emails, two settings are usually sending one each. Check these in order.

1. The form and a logic rule both send email

1. Edit the form and click Confirm in the left menu. Under Settings, Send Email confirmations sends a confirmation when the registrant completes the form.
   
2. Click Logic in the left menu. The List of Logic Rules shows each rule's Action. A rule with the action Send Email to Registrant sends a second email.
   
3. Keep only one:

• To keep the Confirm page email, delete the logic rule's email. If you wanted the logic rule so you could use a custom template, go back to Confirm, and under Select Confirmation choose Use email Template for confirmation email instead.
• To send different emails by attendee type with logic, clear Send Email confirmations on the Confirm page and click Save.

2. Additional registrants get their own

Additional registrants (guests someone registers along with themselves) can get their own confirmation. Certain has two ways to add them, and each has its own email setting. To see which one your form uses, edit the form, click Setup, and look in the Online Form Sequence under Page Layout:

• Additional Registration Add means guests go through their own pages, one guest at a time. Check the Addl Regs page.
• Inline Additional Registration Add means guests are added together on one page. Check the Inline Addl Regs page.

If your form uses Additional Registration Add

1. Edit the form and click Addl Regs in the left menu.
2. Open the Transfer Information from Primary Registration to Additional Registrations panel.
3. Look at Send emails to additional registrations? and Send invoice to additional registrations?. When these are checked, each guest gets their own confirmation and invoice. If the primary registrant entered their own email address for a guest, they get the guest's emails too. Clear the boxes if guests shouldn't get their own, then click Save.
   

If your form uses Inline Additional Registration Add

1. Edit the form and click Inline Addl Regs in the left menu.
2. Scroll to Email Settings at the bottom of the page. There are two choices:

• Do not send email confirmations to additional registrants: guests don't get their own email.
• Send email templates for confirmation email to additional registrants: each guest gets the email template you pick.

3. If the primary registrant entered their own email address for a guest and the second choice is on, they get the guest's email too. Choose Do not send email confirmations to additional registrants if guests shouldn't get their own, then click Save.
   

See How do guest and additional registration forms work?

3. The CC and BCC fields

These fields copy the email to every address in them. If the registrant's own address is in one, they get the email twice. Check both places:

• The cc: box under Select Confirmation on the form's Confirm page (shown in the screenshot in section 1).
• The CC and BCC fields on the email template. Go to Promote > Email Templates > Registration and click the pencil icon next to the template.
  

4. Someone sent it again by hand

A planner can resend any email from the registration: open the registration, click Email > Compose in the left menu, pick a template under Select Email Template, and click Send Email NOW. That sends another copy.

Check the history to see what sent each email

Open the registration and click History in the left menu. Every email gets its own row with Email in the Action column.

• A row like "Registration confirmation for [event name]" came from the form's Confirm page.
• A row with the template name in parentheses, like "(Registration Confirmation) Registration Confirmation," came from an email template. Check the User column to see what sent it.
• Online Form in the User column means the form sent it automatically, for example from a logic rule. A person's name means someone sent it by hand from the registration.
  

Next step: Fix the setting, then send yourself a test registration and check its History.