Preheat oven to 450 degrees.
Let frozen berries stand at room temperature for 15 minutes.
Meanwhile, prepare pastry and line 9-inch pie plate. Bake 8 minutes or until lightly browned. Cool on wire rack.
Reduce oven temperature to 350 degrees.
In a large bowl combine sour cream, sugar, flour, and salt.
Add the blackberries and stir gently to combine.
Spoon filling into pre-baked crust. To prevent over-browning, cover edge of pie with foil.
Bake for 20-25 minutes if using fresh berries, or 50 minutes if using frozen berries. Remove foil.
Bake 15-20 minutes more or until filling is bubbly and appears set.
Cool on wire rack for 2 hours. Serve or cover and refrigerate.