By default, you can assign a resource to a task even if they are over-scheduled.
When this system setting is enabled, Autotask will check the primary resource's availability when the task is saved. This calculation will compare the resource's available time to the start/end dates and Hours per Resource specified for the task. The formula will be the same one that is used by the Workload Report and the calculation is based on back-load distribution (for tasks, tickets, and recurring tickets). For information on the Workload Report, Refer to Workload report.
If the resource is overbooked, or if the assignment of this task will result in the resource becoming overbooked, a message will indicate that the resource does not have enough time available to accommodate the task. You can continue to save the task or cancel and select another resource.
NOTE In order to complete this check, the task must include one or more of the following elements: Start Date, End Date, Estimated Hours, Resource Name.