I use LR on a mac. In developing photos, the sliders on the right side - exposure, contrast, shading went away and I am not able to bring them back. What do I toggle to get them to return?
Control-click on one of the other section headers in the Develop Panel (Tone Curve, Split Toning, Detail etc). This brings up a menu which allow you to re-select to show the Basic panel which you've lost.