Did you have a spouse or child living in Utah during 2010? Did you own property in Utah in 2010? The State of Utah has told my father that absent affirmative proof that he was NOT a resident of Utah, the State would presume that he WAS a resident, and charge him tax accordingly. Resident is anyone who has spent more than 6 months in the State (not necessarily consecutively), or has a dependent spouse or child in the state, plus a smattering of other things.

Personally, I'm pretty sure that they statute they rely on in unconstitutional, because the State should bear the burden of proving that you fell within their taxable jurisdiction, but my dad didn't want to fight it.