Keep getting a pile of sawdust under a window sill. Second floor. House has been treated for termites. Any ideas?

Carpenter bee

Run your finger under the sill. You will find a hole nearly the size of dime.
Sarge

There's no hole. I just went up there since I posted and pulled the bottom piece of trim off and there's nothing to see.

Could it be carpenter ants?

Might be carpenter ants as you stated.

Carpenter ants were doing that in my shed, plastic off the area & fire a bug bomb in there.

A sticky trap will tell the tale.

^this is worth doing.

Yes. I didn't think of a sticky trap.

Sure looks like termites to me

Possibly carpenter ants. I use Bayer Maxforce ant bait killer for ants. Works great. It did what a $1,035 "pest control" company couldn't and for less than $50.

carpenter ants for sure

More than likely carpenter ants. Dry wood termites also do it but I have never seen that much debris left in one place by Dry wood termites. Most of the time if you have Dry wood termites they were brought in the house by purchasing some furniture from across the pond or from out west.

I had that same issue at my camp, turned out it was carpenter ants.

the windows probably have been covered with Aluminum and the carpenter ants are in there in the rotten wood