The window below is displayed at the end of the check-out process when there are documents to be printed. Thes may be invoices, certificates and forms, etc.

Ensure the ones you want printed are checked, and uncheck all the rest. The buttons are as follows:

OK - initiate the printing of the selected documents
Skip - skip the printing
Cancel - abort the check-out
Mail - bring up an email write screen so that the selected documents can be emailed