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 62f041a91..38c16d1ec 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
@@ -442,6 +442,7 @@ public abstract class ResourceAllocation<T extends DayAssignment> extends
     private AssignmentFunction assignmentFunction;
 
     @OnCopy(Strategy.SHARE)
+    @NotNull
     private ResourcesPerDay resourcesPerDay;
 
     private Integer intendedTotalHours;
@@ -1416,8 +1417,10 @@ public abstract class ResourceAllocation<T extends DayAssignment> extends
         return calculateResourcesPerDayFromAssignments(getConsolidatedAssignments());
     }
 
-    @NotNull
     public ResourcesPerDay getResourcesPerDay() {
+        if (resourcesPerDay == null) {
+            return ResourcesPerDay.amount(0);
+        }
         return resourcesPerDay;
     }
 
diff --git a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/ResourcesPerDayModification.java b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/ResourcesPerDayModification.java
index 1993e3c1e..f61abb510 100644
--- a/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/ResourcesPerDayModification.java
+++ b/navalplanner-business/src/main/java/org/navalplanner/business/planner/entities/allocationalgorithms/ResourcesPerDayModification.java
@@ -215,8 +215,6 @@ public abstract class ResourcesPerDayModification extends
             Collection<? extends ResourceAllocation<?>> allocations) {
         List<ResourcesPerDayModification> result = new ArrayList<ResourcesPerDayModification>();
         for (ResourceAllocation<?> resourceAllocation : allocations) {
-            ResourcesPerDay perDay = resourceAllocation.getResourcesPerDay();
-            Validate.notNull(perDay);
             result.add(resourceAllocation.asResourcesPerDayModification());
         }
         return result;