Is it the first one in the list that you printed?
 
I have discovered that if you Click on the list of printed checks it will select/deselect the first one in the list. If you have changed focus from the printed check list to some other window and are ready to go back you must click the Title Bar of the window, or re-select the check that got marked as Not Printed.
 
To fix the problem this is what I would do:
1. Make sure that only the one check that didn't get marked Printed is the one Picked.
2. Print Checks, using the original check number as the first check number, on plain paper.
3. Mark it Printed.
4. Go to AD-B and re-set the Next Check Number to the actual next check number.
 
HTH

Thanks.  I understand what happened and was able to fix it.  Again many thanks