We're moving our usage of Salesforce Marketing Cloud over to a different Salesforce instance. Currently, the subscriber key for each user is their Contact Id, but that obviously won't work once we move everyone over to the new environment and they have a different Contact Id.

Does anyone know how I can edit Subscriber Keys from within ExactTarget or Salesforce?

  • are you moving your SFMC contacts to a SFDC instance or just to a different SFMC instance? Jun 1, 2016 at 17:43
  • It's a new SFDC instance. We're connecting our current Marketing Cloud system to the new SFDC intance.
    – Rochelle
    Jun 1, 2016 at 17:56

2 Answers 2


You have to get SFMC support to do it for you, and it isn't free.

After you insert into SFDC you then have to extract all of those with the new SFDC Ids and the SFMC Ids mapped to one another. Then pass that information over to SFMC support.

I would first contact your SFMC support person to get this going.

I am in the process of going through this right now.

  • Thanks for your reply. Are you just making it so everyone's new subscriber key corresponds to their new Contact Id, or are you using something else like email address? I'm also having a hard time understanding if we need to update the subscriber key at all, since all we ever do is send messages from Salesforce. We never send messages from the Marketing Cloud itself.
    – Rochelle
    Jun 1, 2016 at 18:42
  • 1
    We are setting the subscriber keys to the SFDC Contact Id, this way they will map back and forth through the MC connector. We have lots of journeys/history in MC that we don't want to lose. Which once you enter all the contacts if you sync them up to the MC, they will be new MC contacts as the Ids don't match (unless you have SFMC do the remapping for you). Jun 1, 2016 at 19:37

SubscriberKeys in the Marketing Cloud are immutable in the UI. I would guess that been the "Universal Identifier" (at least in email studio) you wont want people to change it at will.

If you do have a strong business case for this, you would need to engage salesforce in support engagement for a "SubscriberKey migration".

A couple of got'ya:

  1. You have to migrate to totally new susbcriberkeys
  2. It costs ..ALOT
  • Is it possible to: - Take all existing records in SFMC, unsubscribe all of them (or mark as invalid) -Map all of these records to the Contact ID from SFSC - Import all of these mapped records, and import the ContactID as the new subscriber key? Feb 21, 2018 at 16:59
  • Yes it is. The All subscriber list would filter on the subscriberkey. The important caveat is that none of the existing users must have the current SFID as their SusbcriberKey before rapping them, as you would only be able to mapp them to a new key.
    – 0xsegfault
    Feb 21, 2018 at 17:45
  • A risky move would be to delete the subscriberkey from the All sub list. Issue is you lose tracking . I would opt for a subscriberkey migraiton
    – 0xsegfault
    Feb 21, 2018 at 17:45
  • Concern is budget... don't want to spend 10s of thousands for a migration. You would think SF would want to do this on the cheap, or allow third party service providers the ability to complete the migration. Feb 21, 2018 at 21:46
  • Specific to the comment "The important caveat is that none of the existing users must have the current SFID as their SusbcriberKey" This should be fine, since no one in the client is using SFID as the platforms are not connected as yet... Feb 21, 2018 at 21:47

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