The following are the constraints for deleting a task or subtask:
- A task/subtask with a status of Not Started, a custom status associated with Not Started and a task/subtask having no attachment/comment/time entries can be deleted.
- A task/subtask having a status of Duplicate and Duplicate of can not be deleted.
- A task having Blocked, Deferred, In Progress can not be deleted.
Users will need view, edit, and delete permissions in tasks to perform this action. Depending on the user's project permission settings, they may be able to view all project tasks or just a subset. Watchers specifically added to the task will be able to view it.