I use the subsequent formula in my data validation =COUNTA(A2:H2,K2:N2)=12 in column I. It adjusts accordingly to its respective row. Here is a hypothetical: For example, cells A through H and K through N all have values in row two. This allows me to put a value in I2. A day or two later someone else goes and is putting data in the table and accidentally deletes the contents of cell K2. How would I have the user be prompted with the data validation? Currently, there is no prompt of the validation, and the cell remains blank.