I received a question the other day; how to detect duplicate event registrations. My initial though – just create a duplicate detection rule like this:

The rule works fine – but only if the event registration is created in the Dynamics 365 Marketing UI.

Most event registrations however originates from the website/portal hosted event registration form Dynamics 365 Marketing automatically creates for an event

In this scenario the duplicate detection rule doesn’t fire, and a duplicate registration record is created.

But thanks to the fantastic power platform we can easily detect if a contact registers more than once.

Power Automate lets us trigger one or more actions if a new record is created in Dynamics 365.

In this example, we’ll trigger the flow if a new Event Registration record is created.

We’ll then reference the Contact as well as the Event (using the Get Record action). These steps are only necessary if we need details like contact name and event title.

Finally we’ll use the ContactId AND the EventId to filter the full list of event registration records in Dynamics 365 Marketing to see if we end up with more than one record (using the List Records action, and setting the Filter Query argument)

The Filter Query expression looks like this:

_msevtmgt_eventid_value eq @{triggerOutputs()?[‘body/_msevtmgt_eventid_value’]} and 
_msevtmgt_contactid_value eq @{triggerOutputs()?[‘body/_msevtmgt_contactid_value’]}

In this example we’ll simply compose a message if we detect a duplicate registration. Obviously you can do more, e.g. delete the duplicate registration if that is what you logic dictates.

Enjoy the power of one platform – letting you extend Dynamics 365 Marketing to suit your needs exactly.