Recently my 10-100mm f/4.0-5.6 lens suddenly stopped focusing accurately (eventually not at all) on my V1. In autofocus (single point) the focus mechanism would sometimes move and sometimes I'd get the green rectangle, sometimes the red, but focus occurred less and less, then it stopped focusing altogether. There were no impacts and no exposure to water. My other Nikon 1 lenses, the 10-30 and 30-110 both continue to work very well on the V1. Tried cleaning the contacts on the 10-100 but no change. So, through Nikon's frustrating website (they somehow deleted my old (since 2009) Nikon account so I had to create a new one, etc - next time I'll just call) I finally ended up sending it to Nikon's contract service center for that lens - United Electronics Group in Elk Grove Village, IL. Still under warranty, they replaced what they called the "A unit", did their standard cleaning, testing, etc and sent it back. From the time I sent it off until the time I got it back was just over two weeks. Looks like new and works great. Just passing along my experience in case anyone else has a similar problem.