Welcome to the Lightroom User to User Forum.
Please provide some additional info.
What are we talking about LR Version?
Operating System specs etc.?
Is this something just started? Was it working well before?
Any recent changes to your OS or LR?
Hi - Ive just downloaded version 5.6 onto a new mac. Ive had earlier versions on my previous mac with no issue. All the other sliders are fine - its just the exposure slider doesn't operate properly...