I appreciate the effort of downloading QuickBooks 2021 and updating it to begin the activation, @Stuaburt.

Currently, we're working on a new service to help make your move from QuickBooks Desktop (QBDT) to QuickBooks Online (QBO) as smooth as possible. Thus, we aren't able to help you transfer your data from QBDT to QBO until we launch the new migration service.

In the meantime, you can use the open balance method to manually transfer your data from QBDT to QBO.

I'm adding this article for more information: Why can’t I move my data from QuickBooks Desktop to QuickBooks Online?

I'll also add this resource once you successfully converted your data: Post conversion checks for getting started with QuickBooks Online. This will help you get started with QBO.

Let me know if you have other QuickBooks concerns or additional questions about migrating your desktop data to QBO. I'll be glad to lend a helping hand. Have a great rest of the day.