I have the exact same problem, dust of some sort on the sensor or inside of the lens in my HX20V. I had an HX9V before, used it in the exact same way, and after 18 months never experienced this. Nor did I see it happen on any of my previous p&s cameras. 2 months with the HX20V and it has accumulated dust inside. Limited experience of course, but it seems that the HX20V and 30V are particularly prone to letting dust enter the camera... Hopefully Sony is becoming aware of this and will fix whatever design flaw is responsible for this in next year's iteration of the HX series!