I received a 1099 from Vanguard for the sale of my MLP stock. I got a K1 from the MLP. I entered both on my TaxAct program. My question is, am I being taxed twice on the stock sale?
The K-1 generally supersedes the 1099 for MLPs. Look for a "Sales Schedule" included with the K-1, listing the basis and sale proceeds. See also this question.