Hello Guy,

The available from and to are relative to the current date. If you double click on Brian's name to open the Resource Information dialog and enter May 1 in the first available from box, you will see the available to field in the resource sheet say April 30 11:59 pm and the max unit will say zero. Relative to today's day (early April) Brian's max units are zero 12:00 am on May 1.

As a suggestion -- using available from and to dates do not shift tasks assigned to Brian. You might want to consider making the days leading up to May 1 non-working on Brian's calendar instead of the available from/to dates. By changing Brian's working calendar, Project will automatically shift any tasks scheduled prior to May 1 to start on May 1.

I hope this helps.

Julie