Conditional Formatting Greyed Out

[Bludam]

Hi
I am trying to build a gantt chart as per instruction at

but coming unstuck where he uses conditional formatting. He appears to type a formula in a blank cell then copies it to a new rule in conditional formatting
My problem is after I copy the formula I have typed in a blank cell the conditional formatting button on my screen is now greyed out and cannot be used.
Is this just a setting somewhere on my Excel settings?
Thanks in advance

 

[6StringJazzer]

Your screen shot indicates that you are in Edit mode on the cell containing that formula. You can't do anything else when you are in Edit mode. Not only is conditional formatting grayed out, your entire ribbon is grayed out. Press enter to commit the formula and then you should be fine.