After the last Lightroom update the grid showing when using the buttons in the transform tool, like rotate etc. vanished, why is that?
At the bottom of the image area the Show Grid has a slider and an option drop down to set it to Always, Auto and Never. What is yours set to and where on the bar is the slider arrow?
"At the bottom of the image area..."
It is on the Tool Bar which is toggled with the "T" key.