JB,

I am a bit confused. Like described in my initial question, I want the cells already filled to be uneditable i.e. locked, while the ones that are empty, to be ediatable i.e. unlocked. However the code makes all the cells uneditable whether filled or not, so my question how do I make only the ones that are filled, locked whilst the empty cells remain unlocked.

Thanks again.

Oh yeah. I bet you didn't unlock all your cells first, did you?

The default protection state of all cells is "locked" so if you protect your sheet, all cells become uneditable. So turn off the macro, unprotect the sheet, highlight all the cells you want editable and unlock them.

Ctrl-1
Protection tab
[ ] Locked (uncheck this)

And don't take that line of code I mentioned, you do want that in there.