After installing "Second Life 1.20.17 (98669) Oct 5 2008 10:25:42 (Second Life Release)", the windlight water appears to be black as if an oil slick has appeared. This can only be fixed by changing the water environment variable to "glassy" which does not always give the required effect. When going underwater, the ground texture appears black. I vaguely recall this happening before. This does not affect 'off sim' water going into the distance, only that up to the border of the island region. Turning off "Atmospheric Shaders" in Preferences > Graphics appears to make the oil slick feature disappear - but then so does the other Windlight features which are so important to creating an effective atmosphere. Observed at http://slurl.com/secondlife/Knowing%20Hand/219/8/25 but also in other regions. As someone who relies on taking photographs including water to illustrate their work to future clients, this is quite important to me.