I'm new with the SendLogDE but I have searched and found (What custom fields can I include in the SFMC send log? and https://trailhead.salesforce.com/es-MX/content/learn/modules/marketing-cloud-data-management/collect-data-with-a-send-log) that one of the most common custom field is SubscriberKey. So I added to my SendLogDE but it doesn't populate any data. Do you know why?

3 Answers 3


For this answer, I'm assuming the custom field added to the sendlog is named "SubscriberKey".

If you do not have a field in your sending data extension named "SubscriberKey" (as @Swati suggests), you can also set the value for the field using a personalization string (as @David M suggest) or AMPScript variable.

The personalization string for subscriberKey is "_subscriberKey". But since you cannot create data extension fields with a leading underscore, try the following AMPScript.

var @SubscriberKey
set @SubscriberKey = _subscriberkey
  • Hi David, your are assuming well. The field in the sendable DE is called "SubscriberKey" as well. That's why I don't understand why is not getting populated.
    – Annadeli
    Commented May 20, 2020 at 16:30

The custom field names must match the fields in the source Data Extension, that is, the one you use to send the email (your audience). You can also use some personalization strings: Personalization Strings in Email Studio

Just keep in mind you cannot reference personalization strings that starts with underscores.


The field will get populated only if you have a field 'SubscriberKey' in your sendable DE. If you wish to poulate it with subscriber key, you could make a field with the same name which has a send relationship with subscriber key in your DE.

  • Hi. The field in the sendable DE is SubscriberKey. Thats why I don't understand why is not getting populated.
    – Annadeli
    Commented May 20, 2020 at 16:27
  • Once the email is sent, when you query the sent data view for that job, do you see the subscriber key populated? Commented May 20, 2020 at 20:37

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