diff --git a/BealeEngineering/BealeEngineering.Accounts/frmMain.cs b/BealeEngineering/BealeEngineering.Accounts/frmMain.cs
index 09bfed2..e440de6 100644
--- a/BealeEngineering/BealeEngineering.Accounts/frmMain.cs
+++ b/BealeEngineering/BealeEngineering.Accounts/frmMain.cs
@@ -78,9 +78,20 @@ namespace BealeEngineering.Accounts
         private void cmbInvoicePick_SelectedIndexChanged(object sender, EventArgs e)
         {
             var invoiceHeader = (Core.Model.Sale.InvoiceHeader)cmbInvoicePick.SelectedItem;
-            txtInvoiceContact.Text = invoiceHeader.ContactName;
-            txtInvoiceNetAmount.Text = (invoiceHeader.InvoiceTotal - invoiceHeader.TaxTotal).ToString("F") + " " + invoiceHeader.CurrencyCode;
-            txtInvoiceStatus.Text = invoiceHeader.Status;
+            if (invoiceHeader != null)
+            {
+                cmbInvoicePick.Enabled = true;
+                txtInvoiceContact.Text = invoiceHeader.ContactName;
+                txtInvoiceNetAmount.Text = (invoiceHeader.InvoiceTotal - invoiceHeader.TaxTotal).ToString("F") + " " + invoiceHeader.CurrencyCode;
+                txtInvoiceStatus.Text = invoiceHeader.Status;
+            }
+            else
+            {
+                cmbInvoicePick.Enabled = false;
+                txtInvoiceContact.Text = "";
+                txtInvoiceNetAmount.Text = "";
+                txtInvoiceStatus.Text = "";
+            }
         }
 
         private void UpdateInvoiceCombo()