diff --git a/source/java/org/alfresco/repo/usage/UserUsageTrackingComponent.java b/source/java/org/alfresco/repo/usage/UserUsageTrackingComponent.java
index d3a82cc5ee..e7a8c5d14f 100644
--- a/source/java/org/alfresco/repo/usage/UserUsageTrackingComponent.java
+++ b/source/java/org/alfresco/repo/usage/UserUsageTrackingComponent.java
@@ -422,7 +422,7 @@ public class UserUsageTrackingComponent extends AbstractLifecycleBean implements
                 int clearCount = 0;
                 for (NodeRef personNodeRef : personNodeRefs)
                 {
-                    nodeService.setProperty(personNodeRef, ContentModel.PROP_SIZE_CURRENT, null);
+                    nodeService.setProperty(personNodeRef, ContentModel.PROP_SIZE_CURRENT, "0");
                     usageService.deleteDeltas(personNodeRef);
                     
                     if (logger.isTraceEnabled())
diff --git a/source/test-java/org/alfresco/repo/tenant/MultiTDemoTest.java b/source/test-java/org/alfresco/repo/tenant/MultiTDemoTest.java
index beecb33ed8..82aa1a3a22 100644
--- a/source/test-java/org/alfresco/repo/tenant/MultiTDemoTest.java
+++ b/source/test-java/org/alfresco/repo/tenant/MultiTDemoTest.java
@@ -963,7 +963,7 @@ public class MultiTDemoTest extends TestCase
         // find person
         final NodeRef personNodeRef = personService.getPerson(userName);
         // clear user usage
-        nodeService.setProperty(personNodeRef, ContentModel.PROP_SIZE_CURRENT, "");
+        nodeService.setProperty(personNodeRef, ContentModel.PROP_SIZE_CURRENT, "0");
         transactionService.getRetryingTransactionHelper().doInTransaction(new RetryingTransactionCallback<Void>()
         {
             @Override