How to cancel a CSV file upload that I started by accident?
If you started the CSV file upload through the Audiences UI, it cannot be cancelled.
If you started it via a multi (CSV) API call, you may disrupt further import if you remove the CSV file from the Google Bucket.
Please note, that any batches that were successfully imported prior to you removing the file, can't be reverted. If there are any, i.e. a user attribute was uploaded, you can remove it following this guide: How to delete one or more user attributes for users in bulk via CSV upload