When we want to monitor the end of a task, for example, a substantial completion that must be done before a date in a quote, a closeout complete, or even certain phase or floor deliveries that must be completed by a given date, then we should use the deadline field.
If your project due date goes over then the deadline date, in the indicators field an exclamation mark in a red diamond shape will appear to show you that your project will have some delay.
In the total slack field, negative slack days will appear. The total slack will be calculated using the deadline date but the end date will follow the network calculation.
To allow a good calculation of the schedule network, you must not use End type constraints on a task. In fact, we should never use constraints on tasks but only on milestones.
This will not permit a good calculation of the network and there will be scheduling conflict as shown below.
