Drive belt squeal at idle.

[CTScott]

Typically that means that it either is still not tight enough, or that while it was initially squealing the contact surface of the belt glazed (where the friction of it slipping caused the surface to melt enough to become too smooth to grip on the pulleys).

I have a Dayco belt on my red Yaris, that I grabbed because it was the only thing in stock at the store that I grabbed it from. I have had to tighten it three times since the initial installation.