What happens to defects when you delete a user (to save license) and the user has defects assigned to him/her?
You shouldn't delete the users, just make them inactive. See https://confluence.atlassian.com/display/JIRA/Managing+Users#ManagingUsers-Deactivatingauser
It won't let you delete them either, you need to disable them
It looks like you're new here. Sign in or register to get started.