Import CSV File to Data Extension

NOTE This task requires assistance from your eComm Specialist.

Learn how to create a Data Extension as you typically would, then Import over the data from a CSV file. Just remember, you'll need the Contact 18 ID to Import successfully.

Call for Help Importing a CSV file over a Data Extension is simple in theory but more difficult when put into practice the first time. There are some small intricacies that will vary, depending on your use case. Feel free to arrange 30 min. with Melanie Jones to walk through it together.

1 | Create Data Extension

The goal is to create a Data Extension as usual. Access the Marketing Cloud Business Unit that the message will be sent from and configure the Data Extension. There is no need to 'Start' the Data Extension once created.

Required Fields:

  • Contact ID
  • Primary Email (or any Email field)
  • Other personalization fields (like First Name)
  • Contact ID=Key
  • Primary Email Field=Email Address
  • Include any fields used for personalization or dynamic content
  • Overwrite
  • Send Notification to yourself or the user

Click Save in top


2 | Create CSV

There are many ways to go about getting a CSV prepared with the 18 digit ID and desired email field. 

Prepare a spreadsheet with columns including:

  • 18 digit contact ID
  • Email
    • these values can vary in domain
  • other personalization fields

Save as a CSV

See two use cases below:

Some of the campuses recently noticed many employees/students have an incorrect/missing email in their university email field. This issue stems from the source system (Campus Solutions or HRMS) and takes time to remedy. As an immediate work-around, you can Import over the Subscribers in Marketing Cloud that have incorrect/missing emails.

  • Create Report with respective University Email Field
    • Required Columns include: 18 Digit Contact ID, University Email, other personalization fields
  • Export Report
  • Manually input new email addresses in replace of the incorrect ones
  • Save as CSV with columns labeled

Merge multiple Data Extensions (with different University emails) into a single Data Extension. 

Employee Services is a good example of using this Import feature. Typically, when they email across the campuses they send to four different Data Extensions to target four different university emails. We can essentially merge those into one Data Extension so they can leverage A/B Testing and Journey Builder (which don’t support including multiple data extensions).

Create four campus specific Reports with respective University Email Field

Required Columns include: 18 digit contact ID, Email, other personalization fields
TIP! Make sure all your Reports have the same columns

Export and merge these into a single sheet

The Email column will be filled with emails from varying domains

Save as a CSV with columns labeled


3 | Import CSV to Data Extension

Login to Marketing Cloud and navigate to Content Builder

Hover Subscriptions then drill into Salesforce Data Extensions

Select your Data Extension name to open details

Open Salesforce Data Extension Details

Select tab two titled: Records to confirm Subscribers have been added to the Data Extension successfully

Click Import in the top left

View Salesforce Data Extension Records & Import

  • File: find your saved CSV
  • Deliminator: Comma
  • Date Fromat: Leave as Default - English
  • Import Type: IT DEPENDS
    • Overwrite | Removes existing records and overwrites with CSV data
    • Add & Update | Add new records and update existing, will not remove existing
    • Add Only | Add new records, do not update or remove existing records
    • Update Only | Update existing records, do not add new or remove existing records
  • Import Options: Leave as Default - do not check/uncheck anything

Salesforce Data Extension, Import, Upload File

Select Next in the bottom right

STEP 1 | Create Data Extension The Import Type you chose here (Step 3A | Import file Type) depends on your desired outcome. This will also impact if you Start your Data Extension in Step 1 or not.

Select Map Manually

  • Contact 18 ID=Contact ID
  • Email=Email
  • Other fields=other fields

Salesforce Data Extension, Import, Configure Mapping

Select Next in the bottom right

Review your Import details

Select Import in the bottom right

 You’ll receive an email notice once complete. Confirm it is successful.

  • Failed Imports often read a Case Sensitive issue. Confirm you are importing a CSV with Contact 18 ID rather than just the Contact ID (15 digit).


Do NOT re-Start your Data Extension after completing the import. The data you just imported will be overwritten.