SharePoint (and Project Server) Shenanigans

Inactivate task is a new feature for EPM2010; this feature enables the project manager to set certain tasks to inactive rather than deleting the tasks. This functionality is also useful for performing what-if analysis.

The following paragraph from Microsoft explains that intended usage of the inactivate task functionality:

“Microsoft Project Professional 2010 enables you to cancel a task but keep a record of the task in the project plan. This is called inactivating the task. The task remains in the project plan, but does not affect resource availability, the schedule or how other tasks are scheduled. Note: Inactivating a task is a feature available only with Project Professional.
Why would you want to inactivate a task? For one thing, it can help you model the effects of schedule or resource constraints on the project without deleting tasks permanently. Also, inactive tasks remain in the project plan, providing a record of cancelled tasks and enabling you to reactivate them if circumstances change.
Note: Inactivation is nor a good way to archive complete tasks, because it could have unanticipated effects on the remaining schedule. Instead, mark the tasks as completed.”
http://office.microsoft.com/en-us/project-help.inactivate-a-task-HA010370341.aspx

Please see the following best practise guidelines for using inactive tasks:

• When in the planning phase, if you decide that a task or tasks are not required, at this stage use the inactivate task feature to set tasks to inactive rather than deleting the tasks. this will give you the option to quickly make these tasks active at a later date if there is a requirement for these tasks.
• Inactive tasks do not affect resource availability. Baseline values that have already been taken are retained, but any new baselines taken will not include data for inactive tasks.
• Tasks that have actual work cannot be made inactive.
• Inactive tasks are not published, so inactive task assignments will not appear on a team member’s task list.
• Inactive tasks are available to report on via the Project Server OLAP cube, so care should be taken when reporting that these tasks are/aren’t included depending on the figures required. The “Task is Active” field  can be used to include or exclude inactive tasks. If you do not see this field in your OLAP cube, it may be that the EPM administrator has not enabled inactive tasks in the cube.