Lights too bright

[Rhydm]

Hi folks.
My lights are suddenly way too bright in my renders.
To date, I've rendered 54 versions of my project.
All my lights are set at 20%. Up until render 51, all was good.
From then on, all lights are suddently rendering at max and bleaching everything out.
I've tried:
changing the time of day/date
changing the renderer
turning on and off 'add ceiling lights'

At 2 hours per render, I'm pulling my hair out.
Does anyone have a solution please?
Very many thanks.

I'd upload an image, but can't see how..

PS LOVE the program!

[Keet]

A very strange problem. Usually settings don't magically change by themself [:)]
I would first reboot and try again, some system resources might be locked or otherwise interfere after 50 large renderings.

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[MarioSambol]

Keet is right, maybe you changed something in the meantime, upgraded the render or something. In any case, a restart might help...