Overallocation

If a resource is assigned to multiple resources in the same period, it is deemed to be “overallocated”.

On the Scheduling | Schedule tab, in the Resources group: Click Show Overallocated Resources to toggle red highlighting of the names of overallocated resources in the Resources column of the Gantt Chart.

Tip: If the Resources column is not displayed in the Gantt Chart, use the View | Columns option to display it.