Fortunately, I have procedure that I use which overcomes these hurdles.
- Export data to QuickBooks desktop edition. From within QBO, go to Gear | Tools | Export Data. You must do this using Internet Explorer.
- Open exported file in QuickBooks for Windows (latest version).
- If your file just has lists, now is a good time to remove inactive list items, as if you don't, they will import into QBO as "Name (deleted) (deleted)" and will be active again. I use Method CRM to create a routine that removes all of these en masse instead of deleting one by one within QuickBooks.
- Go to Company | Export Company File to QuickBooks Online.
- Import Data into QBO. You can either import just the lists (no balances) or lists and transactions. Again, do this using Internet Explorer.
Note: if you made a mistake and what you have in QBO isn't what you wanted (for example, you missed step 3 above), you can always do the import again. However, you may have to purge the data first. Just change the URL in QBO (https://qbo.intuit.com/app/homepage) to https://qbo.intuit.com/app/purgecompany.