Within Teamwork Projects, you can mark a milestone as complete at any time.
You can complete a milestone directly in the Milestones tab of your project, or when viewing an individual milestone.
To complete a milestone, select the checkbox to the left of the milestone name.
Once a milestone has been marked as complete, you will be able to view it in the Completed tab of the milestones area.
Note: Milestones must be completed individually. Completing all associated task lists does not automatically complete the milestone.
You can also reopen a completed milestone by deselecting the checkbox to the left of the task name.
As well as in a project, you can also complete and reopen milestones in the Everything section of your site.
For more information, see: Adding a milestone