excel - Conditional formatting won't update without double clicking cell in target range

Question

I've made an excel timetable with days and times as columns and rows, respectively. Ive created a conditional format to highlight the current day, time and corresponding cell.

When the current time ticks over into a new 1/2 hour interval the conditional format doesn't automatically change and instead just goes blank as though it's stopped working (and yes I've got 'Calculation Options' in the 'Formulas' tab set to 'Automatic').

When I double click the reference cell (e.g. the time row corresponding to the current time) and click off it, it works. This is obviously not ideal - any suggestions would be great.

I have seen this issue raised but haven't had any satisfactory solutions.

标签： excelvba