You might start by reinstalling CheckBook Pro, just so we're sure you have a solid copy of the app in place. To do that, drag the existing version to the Trash, then visit our site at
https://www.splasm.com/checkbookpro/upd ... plasmstore and follow the directions below where it says "Splasm Store Users", there. After that, if issues persist, you'll want to try manually copying a fresh backup over from the MacBook to the iMac. Then, be sure CheckBook Pro isn't running and double-click the copied-over backup, to see if that helps clear things up.