Cannot update Drupal core through Drush

I am following the tutorial here to update Drupal 7 core using Drush:

This is through the Drush console in Acquia Dev Desktop. I run the command

C:AcquiaWebsitesdrupal-7.61>drush archive-dump 

That gives an error:

exception ‘InvalidArgumentException’ with message ‘The paths must be strings. Got: NULL’ in                      [error]

Or if I try the update core command:

C:AcquiaWebsitesdrupal-7.61>drush pm-update drupal

That gives an InvalidArgumentException error when I type “y” to confirm that yes I do want to continue. What am I doing wrong?

Drupal version: