Hi guys,

I need a simple help. i'm creating a spreadsheet but i can't get past an issue.
I need to disable a certain cell if another cell is filled, meaning:

If cell A1 is filled then cell B1 is blocked, so no data can be filled.
If cell B1 is filled then cell A1 is blocked, so no data can be filled.

If i delete the data in any cell (A1 or B1) then both cells become enabled.

Thanks in advance.