What happens if I buy a home at an auction that has a mortgage?

This is a very technical, evolving area of law. If the HOA was established before the mortgage was recorded, the HOA's lien takes precedence over the mortgage up to 9 months worth of delinquent HOA payments. The State of Nevada has taken the position that costs of collection by the HOA (attorney's fees, costs of foreclosure, interest, late fees, etc.) are not included in the lien. Many HOA's take the opposite position. The issue is before the Nevada Supreme Court right now, and we are waiting or a decision. You can establish that the mortgage was foreclosed (wiped out) only through filing a lawsuit called a quiet title action in Nevada court. You won't be able to get title insurance without a court order in your favor. But, it is possible to prevail in court if the foreclosure was handled properly. I am handling a quiet title action right now, and there are a few lawyers in Las Vegas who know what to do in this situation.

Your question is confusing. It is best for you to talk to a good foreclosure attorney licensed in the state where the property is located rather than me guessing at what you mean and the facts.

At an auction, you take the property subject to all liens ahead of you.

No, the property owners lost all rights in the tax foreclosure. I am assuming the county sold it because of past due taxes. If there is still a mortgage on the home, you will have to make arrangements with the mortgage company, or they can foreclose and take the home back.