Troubleshooting duplicate or missing identifier error messages

You will learn

Learn about duplicate or missing identifier errors and how to resolve them in your list uploads.

If you’re encountering a different error message, head to our guide on troubleshooting list imports.

Find skipped records

1. Open your list and select the Imports tab. It shows imports from the last 7 days.
2. After the import finishes, click Download error file for that import, if the button is available.
3. Open the downloaded CSV and review the Errors column to identify which rows need correcting.

If Download error file is unavailable, check your original CSV for the issues below.

Duplicate identifiers

Duplicate identifier errors occur when rows repeat the same identifiers or are identified as the same profile. Identifiers can include email addresses, phone numbers, and external IDs. Klaviyo does not always keep the first row.

Compare the duplicate rows and keep 1 row per contact with the values you want to import. If the rows belong to different people, correct their identifiers before reimporting. Reimported values can overwrite existing profile properties.

Missing unique identifiers

Missing identifier errors mean that a row has no value in a mapped identifier field, such as Email, Phone Number, or External ID. An empty identifier field can also be reported as an invalid email address, phone number, or external ID.

Add an email address, phone number, or external ID for each affected contact. If the value is already in your CSV, make sure its column is selected for import and mapped to the corresponding Klaviyo property.

Reimport the corrected file

1. On the Imports tab, click Upload new file for the import you are correcting.
2. Upload your corrected CSV.
3. Map each column you want to import to its Klaviyo property. If you are using the downloaded error file, deselect the Errors and Warnings columns so they are not imported as profile properties.
4. If Next appears after mapping, click it and confirm the contacts’ consent status. Only apply consent that your contacts have given. Click Import to start the import.

Klaviyo returns you to the Imports tab, where you can check the new import’s progress and results. For the full import procedure, see How to import subscribers to a list.

Additional resources