@dmacphee@AskPippa Without any details (LibreOffice version, operating system etc.) then I'm afraid we can't. Pippa, try asking on https://ask.libreoffice.org with details about your setup, and someone should be able to help you!
So, why is it every time I launch LibreOffice, a black window appears saying "Waiting for printer to respond" and won't go away until I hit Cancel. And then the document finally opens? If there is a setting to change, I don't know how to find it. Hints welcome.