Upload list to Marketo with existing members - Duplicate or Update?

[Hadar_Ron]

Hi,

When I'm uploading a CSV list into Marketo and in the list I have a few members that already exist in the system (Marketo/SF), Marketo create a new member or update the existing member (can be lead or contact)?

In addition to that, how Marketo define new members? By email address/First Name or something else?

And how can I edit it? 

Thanks in advance!

Hadar

[TBlane_McMichen · Accepted solution]

Hi Hadar,

Marketo will not create a duplicate lead.  The only required field for a lead is "email address", because this is the key field.  As long as the email is the same, a new record will not be created.  It will update other field values, like name, etc., unless during the import you tell it to ignore a column from your import in the field mapping step.  This will ignore the column for all records.

Import a List of People - Marketo Docs - Product Documentation 

[SanfordWhiteman · Accepted solution]

Fields are overwritten completely, not appended, when you import.

If you want to append to a history field, then have that field be separate from the import. Include another custom field, MostRecentPersonNote in the import. Then use the Flow step Change Data Value to append the most recent value. 

You can search here for "history field" and get more pointers.