When is a duplicate lead created?

[Anonymous]

We have a duplicate lead and contact. The contact was created back in sfdc 2012. However, the lead was uploaded to mkto recently and they both have the same email address. Why was a duplicate record made in sfdc?

 

[Adam_Vavrek1]

Hi D,
Do you have a recurring campaign that removes leads from Marketo?
When you search for the email address in Marketo's Lead Database, do two records appear?

[Anonymous]

I don't believe we have a campaign to remove leads from Marketo. When I search for this person's email address in Marketo there is only one record.

 

[Adam_Vavrek1]

One of those leads must exist in SFDC and not Marketo. Since there is only one lead with that email address in Marketo, Marketo did not make a dupe record.

[Anonymous]

Adam - can you please clarify why a dupulicate was created in sfdc?

[Adam_Vavrek1]

The original lead existed in Salesforce and not in Marketo which is why Marketo didn't recognize the duplicate and pushed the new lead over the Salesforce. 

[Anonymous]

Correct me if I wrong, but if this lead - let's just call him David. If David originally existed in SFDC back in 2012 wouldn't he have been created in Marketo, too, considering both systems are bidirectionally synced? Then a user recently uploaded David's duplicate in MKTO (MKTO did not create a dupe), but SFDC created David again with the same email address.

If it's easier = So before the upload, there was a David in MKTO and a David in SFDC. Then he was created again (via MKTO) with the same email address which created the dupe.