An IT project’s schedule will change throughout the lifecycle. One decision project managers sometimes have to make because of these changes is whether a task should ever be deleted from a baselined plan.

If a task is deleted, you lose all the baseline information and any work or costs associated with the task. And as the project executes, you may want to compare the current project against the original baseline or conduct a what-if analysis.

Prior to Microsoft Project 2010, the alternative to deleting a baselined task involved reducing the project duration to zero. I applied this approach to some of my projects, and it wasn’t ideal because creating a zero duration task also converted the task into a milestone. This caused problems in milestone reporting, and if the task was added back, it caused even more confusion.

Microsoft Project 2010’s inactive tasks feature

Microsoft Project 2010 resolves a lot of these issues with its inactive tasks feature. This feature allows you to remove tasks from the schedule and recognize the task existed in the original plan. The inactive tasks feature also allows you to do some what-if analysis when assessing a potential change to your project schedule without losing the original schedule data.

I find the inactive tasks feature useful when I’m reassessing the critical path and considering changes to a project schedule. Instead of saving different versions as I examine what-if scenarios, I can inactivate and back out of the changes as necessary.

How to inactivate a task
To set a task to inactive status, click on the task. Then, in the Task ribbon in the Schedule section, click the Inactivate icon (Figure A). The task will appear grayed out with a strike-through line (Figure B).
Figure A

Inactivate a task. (Click the image to enlarge.)

Figure B

Two of the five tasks are in an inactive status. (Click the image to enlarge.)

When a task is inactivated, the task and its associated budget, work, and assigned resources are not included in the project schedule calculations.

What to consider before inactivating a task
An inactivated task will impact the project schedule; you will need to reassess the resource leveling and its impact to the critical path. In Figure C, the original project schedule is displayed with properly leveled resources and the critical path identified.
Figure C

Examine the original project schedule. (Click the image to enlarge.)

After inactivating tasks, the project schedule has overallocated resources that need to be rescheduled (Figure D). Reallocating the resources manually or automatically will change the start and finish dates.
Figure D

Inactivate tasks. (Click the image to enlarge.)

Figure E depicts the revised schedule with inactive tasks, a new critical path, and adjusted resource allocations. (Another way to hide the inactive tasks is to change the filter to Active Tasks in the View ribbon bar.)
Figure E

Vuew resource leveled and inactivated tasks. (Click the image to enlarge.)