Yet again, Intuit "support" gives a response that's incorrect. The IIF export is only for lists, not transactions. And if you export transactions into Excel, there's no way to convert that into an IIF without paying a lot of money for 3rd party software.

After so many years and iterations, you'd think that Intuit would make it possible for us to merge company files or import transactions from one company file into another, rather than spending 100 hours re-inputting all the data manually.

The ongoing ineffectiveness is why I stopped using QBO and told clients that upgrading to newer versions was a waste of money.