need some help with understanding exactly how this works.

First, our setup:

  • We have Salesforce CRM and Marketing Cloud
  • Connector is up and running, syncing contacts over to MC
  • We have a "Master Send DE" which is updated daily via automation
  • We send to this Master Send DE

My understanding of expected behaviour:

  • You have a subscriber with their SubscriberKey and EmailAddress on All Subscribers (assume they are Active)
  • You send to a DE with the same SubscriberKey but a different EmailAddress
  • Send is successful
  • Search All Subscribers using SubscriberKey and the EmailAddress is now changed to the one used in the recent send

I have tested this and it behaves as described above.

Problem I've run into

  • We sent out an eDM to our customers yesterday
  • One of our devs received the email that should have gone to a customer (his email is against that customer's SubscriberKey on All Subs - mistake made during testing API - long story)
  • The Master Send DE, however, has the correct customer email address against their SubscriberKey, so...
  • Based on the above expected behaviour, the email should have gone to the customer's email address regardless and that email address should now be stored against the customer's SubscriberKey on All Subs
  • But this is not what happened...

How is this possible? Are there some kind of exceptions to this rule (for example, a DE uploaded manually vs a DE populated via automation?). Or any other reason the expected behaviour didn't happen?


1 Answer 1


The understanding of expected behavior is wrong, the last point of expecting the Email to be updated does not happen.

So whatever you tested was definitely not working the way you described above.

Meaning any Email sends done to a SubscriberKey that exists in AllSubscribers will always be sent to the Email address listed in the AllSubscribers table, not to the one in your Data Extension or List.

In order to have the latest Email changes from Salesforce CRM reflected in the AllSubscribers list, you will need to build an Automation to actually update it to be so.

  • Hi Rain, thanks for the response. However, this is what I tested: - Have existing subscriber with Key of 12345 and email of [email protected] - Upload a single record to DE, where record has a Key of 12345 and email of [email protected] - Send using that DE as the audience (so send to 1 person) - Go and search subscriber key of 12345 on All Subs - The email address is now [email protected]. I have tested this twice now. So not sure on what basis you are sure it's wrong, but I can assure you that is what is happening. If my steps above are wrong in some way, please let me know.
    – Ben
    Mar 14, 2019 at 3:39
  • Your test scenario described does not apply in 2 MC instances I tested it, the Email Address in AllSubscribers is not updated automatically in four different Email send types I tried. This is also confirmed by documentation on this topic ( help.salesforce.com/… ) However, after a call with SFMC support they told me there exists a business rule that can be turned on that would indeed update the Email Addres. I assume this is most likely what has been configured in your instance.
    – Rain
    Mar 14, 2019 at 8:34
  • Hi Rain thanks for clarifying, that documentation is what I was looking for. It sounds like we do have some kind of custom business rule setup. I have opened a case with support to check on this.
    – Ben
    Mar 15, 2019 at 0:15
  • @Rain when I reviewed the help article it demonstrated BOTH scenarios to be possible: 1) If the Sendable DE is a regular DE, then the All Subs email is used. 2) If a SF DE is used, then the email from the SF DE is used and All Subs is overwritten. Has someone confirmed this? Nov 10, 2020 at 2:28

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