Duplicate Created if Lead Already Exists in MKTO then created separately in SFDC?

[Max_Maurier]

Premise: Say we create a lead in Marketo and don't sync it to SFDC. Next, the same lead is created on the SFDC side and synced to Marketo.

Will this create a duplicate lead on the Marketo side since it doesn't have an SFDC ID?

[SanfordWhiteman]

Yes. There's no way for Marketo to know this record represents the same lead (remember, email address is not actually a unique identifier, merely a primary dedupe key for some entry points into the system).

[Grégoire_Miche2 · Accepted solution]

This is why we always recommend not doing this.

As soon as a lead is created in Marketo, push it to SFDC and assign it to a lead queue, until it's ready for sales, inside sales or telemarketing assignment. Lead queues offer a very flexible mechanism in SFDC to store leads and more or less hide them from the sales.

-Greg