Nprinting - User Import task fails with "email_address" violates foreign key constraint

When running an NPrinting import task with the option:
 
“Remove users added in a previous run of this task, if not present in the import file”
Checked
 
You receive the error:

ERROR message : importing USER : ERROR: 23503: update or delete on table "email_address" violates foreign key constraint "fk2845be5917196dd2" on table "smtp_destination" ERROR message : Import task execution failed. No data was saved.

The task fails as it cannot remove a user which has been removed from the import file but is still linked to a publish task.

Environments:
NPrinting 17 and 18

You can't delete a user which is which is still tied to a publish task.
 

Option 1.  As a general workaround so you can complete the import task. You can disable the option "Remove users added in a previous run of this task, if not present in the import file" when setting up the task, this will allow the task to run through completely, but it will not clean out all old users.

Option 2. If you have only a small number of reports.  Check through the publish tasks manually and identify where you've used a custom "from" user/email address which no longer exists in the import file.

Option 3. Using PGAdmin run the following query to determine the tasks that have a custom sender.
 

SELECT t.name, e.email FROM smtp_destination s     JOIN destination d ON(s.destination_id = d.id)     JOIN email_address e ON(s.from_id = e.id)     JOIN task t ON(d.publish_report_task_id = t.id) UNION SELECT t.name, e.email FROM smtp_destination_to_bcc s     JOIN destination d ON(s.smtp_destination_id = d.id)     JOIN email_address e ON(s.email_address_id = e.id)     JOIN task t ON(d.publish_report_task_id = t.id) UNION SELECT t.name, e.email FROM smtp_destination_to_cc s     JOIN destination d ON(s.smtp_destination_id = d.id)     JOIN email_address e ON(s.email_address_id = e.id)     JOIN task t ON(d.publish_report_task_id = t.id) UNION SELECT 'Default sender' AS name, e.email FROM smtp_configuration c     JOIN email_address e ON(c.default_sender_id = e.id);

For example if I a default sender from of reporting@qlik.com and have two publish tasks with custom "from" address called in the email message section of the task:
QlikTestReport1
QlikTestReport2

Which have a custom from address as: customreportemail@qlik.com

Executing the above query this should give you a result

name	email
QlikTestReport1	customreportemail@qlik.com
QlikTestReport2	customreportemail@qlik.com
DefaultSender	reporting@qlik.com

Now you've identified the report name you can find this in the NPrinting console and change the sender option from custom to default sender.