diff --git a/ReportImp/ArcheTecklenburg/Invoicing/CollectiveInvoiceCreation.cs b/ReportImp/ArcheTecklenburg/Invoicing/CollectiveInvoiceCreation.cs
index a0d126357..15bdcf834 100644
--- a/ReportImp/ArcheTecklenburg/Invoicing/CollectiveInvoiceCreation.cs
+++ b/ReportImp/ArcheTecklenburg/Invoicing/CollectiveInvoiceCreation.cs
@@ -126,7 +126,7 @@ namespace ArcheTecklenburg.Invoicing
             var data = calc.GetFixedBillingData(supportConceptApprovalPeriod, serviceInvoicePeriod.Start, serviceInvoicePeriod.End);
             var scap = supportConceptApprovalPeriod;
 
-            if (scap != null && scap.ServiceCategory != null)
+            if (scap != null && scap.ServiceCategory != null && scap.StartDate.HasValue && scap.EndDate.HasValue)
             {
                 IList<InvoiceItem> ergebnis = new List<InvoiceItem>();
                 var customer = cb2sc.SupportConcept.Customer;