Thanks for the rapid response Rea. I actually tried this and got exactly the same error. It seems this Novo account is some kind of default account for something but I cannot figure out what. The same error occurs when I try to merge. That is - I disconnected Novo from online banking, tried the merge following the directions given, and still get the same error about Novo checking being reserved for a default account, whatever that means.

So I have re-enabled online banking and am resetting all of the downloaded transactions, but I still have this "Cash" account. What is adding insult to injury for me, is that I can clearly see in the Audit Log, that this Cash account was created by "System Administration" during the payroll process operated by QBO "Full Service Payroll". That is - someone, or something, created that Cash account, directed payroll transactions to it, and essentially left these orphan transactions in that account (see attachment, if you can). 

Still, what would be a nice fix of merging the accounts is not something QBO will let me do. Is there any other solution - merge them back the other way? Merge them both into a new, third account? Create a Bank account, make them both subaccounts, then somehow merge them that way?

Thanks for the help!