We have a standard calendar work week. (Monday to Friday with weekends off)

Our resources have "standard" calendar - so scheduling as standard for them is a normal work week.

However, we have operational sub-tasks that sometimes need to happen on a weekend - in non-working hours for our resources. The weekend tasks are dependent on other normal predecessor tasks completing. ie. the weekend task occurs on "the first available weekend after completion of the predecessor task".

From a task perspective this is easy to achieve. We simply create a "weekend calendar" and make the task part of that calendar - the task then naturally schedules itself on the first weekend following completion of the predecessor task/s.

To allow scheduling of the Resources in their "non-working" hours, we on the Task we tick the checkbox Scheduling ignores resource calendars

The Task is created normally and a little red man is displayed in the information column on the left (on the Gantt chart view). Right clicking on the little man causes MS Project to say "Resources assigned in non-working time" - which is fine. This is what we want.

So all looks great.

....until I try to level the resources. At which point MS Project hangs completely and I have to crash out and restart.

It seems to me a basic requirement for a PM tool to cater for adhoc scheduling of resources outside their normal work calendar on dates determined by the natural flow of Tasks (as opposed to saying "on the 5th of May, create this special exception"). And that ticking the "ignore the resource calendar restrictions for this task" should allow this.

I am therefore hoping that I am missing some basic consideration. Any help would be greatly appreciated!

1 Answer 1


Don’t ignore resource calendars... If you know which team member will be responsible to do the work outside of the business hours, you should change this resource calendar, marking the after hours activity time as working hours for this resource.

Just keep in mind that ad-hoc activities may be a sign of problems in your project. If they are scheduled, they are not ad-hoc, if these activities are part of risk/issues response planning it is ok to add these tasks to the schedule, if none of these situations mentioned applies you are likely adding scope to your project or have a poorly defined WBS. Watch out!

Adhoc planning/adjustments of resources is common and necessary. You are likely be dealing with human beings, that get sick, have kids that get sick or have other emergencies that are impossible to predict. So this shuffling and replanning is normal. Ignoring it may be dangerous as, depending on your project characteristics, you may incur in cost-overrun without noticing due to different resource rates.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.