diff --git a/server/AyaNova/biz/WorkOrderBiz.cs b/server/AyaNova/biz/WorkOrderBiz.cs
index 5ba9e01a..1abfd6d6 100644
--- a/server/AyaNova/biz/WorkOrderBiz.cs
+++ b/server/AyaNova/biz/WorkOrderBiz.cs
@@ -356,7 +356,7 @@ namespace AyaNova.Biz
             left join aworkorderstatus on (aworkorder.laststatusid = aworkorderstatus.id)
             left join aproject on (aworkorder.projectid=aproject.id)
             where 
-            aworkorder.invoicenumber is null
+            (aworkorder.invoicenumber is null or aworkorder.invoicenumber='')
             {statusFragment}
             order by aworkorder.serial asc";
                 using (var dr = await command.ExecuteReaderAsync())
@@ -1689,7 +1689,7 @@ namespace AyaNova.Biz
             {
                 if(newObject.UserId==0)
                     newObject.UserId=UserId;
-                    
+
                 await ct.WorkOrderState.AddAsync(newObject);
                 var wo = await ct.WorkOrder.FirstOrDefaultAsync(x => x.Id == newObject.WorkOrderId);
                 var newStatusInfo = await ct.WorkOrderStatus.AsNoTracking().FirstOrDefaultAsync(x => x.Id == newObject.WorkOrderStatusId);