In my worksheet for the column C, I have the data validation set to =ISNA(MATCH($C1,OffDays,FALSE)), where OffDays is a list on another sheet that does not allow users to input those dates.

I want to create a macro that will search through column C when clicked and on error, display an input box that will allow users to input a date so the cell no longer contains the data validation error.

I would also like the box to come up when someone inputs a value that triggers the data validation error, so they can type in a new date.

Any ideas?