Hey there, @bellevuefineart.
I'm happy to help out with the duplicate client issue. Duplicate Clients in QBO can happen for many different reasons, but the most common one occurs when choosing a Client's name on Invoices. Ensure that you're choosing the Client's name from the drop-down list and not typing and hitting Enter unless their existing profile is selected, as it can create a separate Client.
I also recommend clearing your cache and cookies to ensure that they aren't causing your browser to register inputs multiple times.
Please know I'm always available here to lend a helping hand. Have a great weekend!
