If you are not able to close a check from the workstation, you can try the Check Closing option.
Check Number
You must enter the 6 digits number of the invoice
If the check had already been pre-authorized with a credit card, it will be closed in that media type. Otherwise, it will be closed to Cash.
NOTE: This option is a utility that is used in special cases only. This is not the normal method to close a check.