Volume light disappear

[Diurno]

Hi guys, i'm working on a scene for an animation; and i insered some volume lights. Today everything worked fine, since i dunno why, these lights are disappeared.... i've tried all, delete all the object except for the light; delete all the texture, cleared all pass effect..... nothing...

i have no more idea of why these lights are gone.... so i ask for help.... if you know some common problem with the volume lights.... mabye an incompatibility with something.....

[Grubber]

I have similar problem in Softimage 7.5.
To solve this I simply delete the light, restart Softimage, and set it up again. Though I am lucky I used only one volume light and it was only for a still.

[Diurno]

well, i've about 20 lights..... but the big problem is that if I create a new one, and make it a volume, it doesn't work....

[Grubber]

well, i've about 20 lights.....

I also tried to merge my scene into new one. That helped... for a while...