diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
index e6f9ca5e3..096ea268c 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/ResourceAllocation.java
@@ -200,6 +200,24 @@ public abstract class ResourceAllocation<T extends DayAssignment> extends
                     allocation.setResourcesPerDay(resourcesPerDay);
                     allocation.resetGenericAssignmentsTo(dayAssignments);
                 }
+
+                @Override
+                protected boolean thereAreAvailableHoursFrom(
+                        LocalDate start,
+                        ResourcesPerDayModification resourcesPerDayModification,
+                        int hoursToAllocate) {
+                    IWorkHours workHoursPerDay = resourcesPerDayModification
+                            .getBeingModified().getWorkHoursPerDay();
+                    ResourcesPerDay resourcesPerDay = resourcesPerDayModification
+                            .getGoal();
+                    return workHoursPerDay.thereAreAvailableHoursFrom(start,
+                            resourcesPerDay, hoursToAllocate);
+                }
+
+                @Override
+                protected void markUnsatisfied(ResourceAllocation<?> allocation) {
+                    allocation.markAsUnsatisfied();
+                }
             };
             return allocator.untilAllocating(hoursToAllocate);
         }
@@ -530,6 +548,9 @@ public abstract class ResourceAllocation<T extends DayAssignment> extends
             @Override
             public boolean thereAreAvailableHoursFrom(LocalDate date,
                     ResourcesPerDay resourcesPerDay, int hours) {
+                if (getTaskCalendar() == null) {
+                    return true;
+                }
                 return getTaskCalendar().thereAreAvailableHoursFrom(date,
                         resourcesPerDay, hours);
             }
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/AllocatorForSpecifiedResourcesPerDayAndHours.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/AllocatorForSpecifiedResourcesPerDayAndHours.java
index 1fd907a93..f079bd469 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/AllocatorForSpecifiedResourcesPerDayAndHours.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/AllocatorForSpecifiedResourcesPerDayAndHours.java
@@ -75,6 +75,11 @@ public abstract class AllocatorForSpecifiedResourcesPerDayAndHours {
             Integer hoursToAllocate) {
         int hoursRemaining = hoursToAllocate;
         LocalDate start = new LocalDate(task.getStartDate().getTime());
+        if (!thereAreAvailableHoursFrom(start, resourcesPerDayModification,
+                hoursToAllocate)) {
+            markUnsatisfied(resourcesPerDayModification.getBeingModified());
+            return 0;
+        }
         int day = 0;
         while (hoursRemaining > 0) {
             LocalDate current = start.plusDays(day);
@@ -105,6 +110,12 @@ public abstract class AllocatorForSpecifiedResourcesPerDayAndHours {
     protected abstract List<DayAssignment> createAssignmentsAtDay(
             ResourcesPerDayModification allocation, LocalDate day, Integer limit);
 
+    protected abstract boolean thereAreAvailableHoursFrom(LocalDate start,
+            ResourcesPerDayModification resourcesPerDayModification,
+            int hoursToAllocate);
+
+    protected abstract void markUnsatisfied(ResourceAllocation<?> beingModified);
+
     private int assignForDay(
             ResourcesPerDayModification resourcesPerDayModification,
             LocalDate day, int remaining) {