Probate Problems

What is the name of your state? - PA

My grandmother passed away 11 years ago, and her estate passed via intestate succession to my mother and her 4 brothers and sisters. My mother was the court appointed administrator. Inheritance taxes were paid and two of three properties were sold, but the estate never went through probate. Now I want to either purchase the third property or have them give it to me. Will we need to go through probate now, after 11 years?

Yes, probate is needed in order to legally determine and record exactly who has ownership and who the legal heirs are.

For what reason was the estate never probated?

There is no reason that I know of. Does this mean that the other two sale transactions are invalid?

No, it doesn't mean they were invalid, since your mother had legal authority to do the sales.