Within Teamwork Projects, any file that has been attached to a task can also be removed at a later date.
To detach a file from a task, navigate to the Tasks area of your project.
Locate the task which has the file attached and select it to open the task details view. Here, you will see a list of the attached files below the task and an option to Manage Task Attachments.
When you select this, you will see a checkbox option next to each file that have been attached. To remove a file, uncheck the box next to the file and select Save Changes.
For more information, see: Adding a file to a task