Unable to import Inv. b/c Sales Tax is setup. One wrong entry posted to sales tax has been reversed. Due to that QBO is not allowing me to turn it off to import Inv.

Thank you for posting your concern in the Community, @cari2.

As of this time, the option to import your invoices with sales tax turned on, is unavailable in QuickBooks Online (QBO). This is why turning it off triggers an error. Rest assured that our development engineers are still working to make this function available to our customers. 

In the meantime, you'll want to consider visiting the QuickBooks App Center and look for a third-party app that allows you to import invoices with sales taxes into QBO. Alternatively, you can follow these steps in searching for one within QBO:

1. On the left side menu, select Apps
2. Click the Find Apps tab.
3. Look for an app on the search bar.

For your future reference, check out this article about personalizing the look and information of your sales forms: Customize invoices, estimates, and sales receipts in QuickBooks Online.

I'll be on the lookout in the comment section if you have more invoice and QuickBooks-related concerns. Stay safe.

Thank you Faith!  Sales Tax was setup but we've never collected any.  There was 1 erroneous entry to a sales tax account a couple years ago and was reversed.  Nothing since has been recorded and I'm still not able to off Sales Tax or import invoices.

@cari2 

You may have 2 options

1. Use an importer tool

https://get.transactionpro.com/qbo

2. Purchase a 3rd party service to migrate your data to a new QBO account.