I have this bug occasionelly at the opening of a PZ3 file.

That's not a bug, that's a negative light. Some people use these to "suck" light from an image and make shadows deeper. You'll find Sydd uses them a lot as do some other artists. Just select the thing and click on the trash can icon to get rid of it if you don't want it there. The negative lights are one of the few lights that Poser leaves behind even after resetting the lights, annoying but not world shattering. :)

I'have never crte this light, I can't control this light. and when I delete the light all of the others lights are altered in intensity and the renders is very very very dark

Which just goes to prove that the speed of dark is faster than the speed of light. Because when you turn the light off, the dark is already there :)

You have an even bigger bug! All the words in the menue bar are scrabled ;-) Think of it this way, when you open a "PZ3" you are opening someone elses actual saved Project, lights, props, and all. If you delete the light then you will have to reset the others to what 'you want' the scene to be. 'Negative' light for better shadows? I'll have to play with this one :-)

No help, but I like the way that render turned out with "negative lights". :) GrayMare

Just one thing i see you have Metacreation version go to Curious Lab to find the last patch. BoF