This IS quite annoying/stupid.
 
I setup sale Tax for onlY ONE state, but the TAX show in every order summary before customer go to the payment, even it will not really charge customers from out states, but the Tax entry, turn off all the customers (from placing orders!!!).
 
I removed all the Tax -related (display) in product/item property page, but it will still show up.
 
This is NOT acceptable.
 
Please resolve this ASAP.
 
Thanks.

Many kudos to Viart support team,
 
This is resolved, you need to remove any default state (to none) in the Administration > System > Global Settings.
 
In case if you have this problem.
 
EP