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The contact import failed

Reviewed on 5 October 2026

You uploaded a CSV of contacts and the import did not finish as you expected. Check these causes in order, from the most frequent to the least frequent. Each one says how to recognise it, where it shows and what to do.

The import has stopped

How to recognise it

The import has stopped. The contacts saved up to that point are kept. appears. The import was cut halfway, for instance by a one-off failure while saving.

Where to check it

You see it in the last step of import contacts, in place of the summary of the import.

What to do

Upload the same file again. The contacts that already came in keep their data and get the tags again, without duplicates. Import contacts from CSV explains it.

The file is over the limits

How to recognise it

The upload does not start and the wizard warns you about the size. The CSV takes up to 50,000 rows and 20 MB.

Where to check it

You see it in the first step of import contacts, when you choose the file.

What to do

Split the file into several of fewer than 50,000 rows and upload them one after the other with the same columns.

Some rows were discarded

How to recognise it

The import finishes and the summary counts the rows that did not come in. It happens with misspelled emails, repeated rows or people who unsubscribed on OnBio, who stay unsubscribed even if they come in the file.

Where to check it

You see it in the summary of import contacts, with the number of discarded rows.

What to do

Click Download discarded rows to see each row with its reason. Correct those with a mistake and upload them in another file.

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