Data Validation and Vlookups together

[certain_death]

Hi all

I have this formula in a cell that checks if cell U99>a date and also if W99 is not blank.

=IF(IF(U99>VLOOKUP(E13,ENDDATE,2,0),TRUE,0)*(W99<>0),"INCORRECT FORECAST"," ")

I want to build this into data validation somehow so if the formula returns "INCORRECT FORECAST", it will not let you overtype the cell and display a message, if it is not "INCORRECT FORECAST" it will let you type in cell

I know how to use Data Validation but I dont know whether you can use the two together in one cell

Can anyone help please?

Thanks
Mark

[zbor]

Why would you like to type in cell over formula?!