I have a bad window leak. The water comes in during rainy days and makes its way from the 2nd story window to the first floor window and wall just below it. After much painful cluelessness I finally have a lead on a cause. Today it rained and I got heavy dripping coming from a hole in the bottom right corner of the frame.
I think what is happening is that black goop (silicone?) that is all over the window has clogged up the weep holes. The water pools up and spills back into the house. There's a small crack in the wall on the right probably from water and that may be where the drip makes its way down to the first floor. You can see this happening realtime in the video 25 seconds in ending about 35 seconds in.