We cannot get Excel to issue a validation error when a value is deleted from
a cell. The cell validation is set up to only accept the whole number 39.
In addition, the option to ignore blanks has been manually unchecked.
Finally, we have created a validation alert message in the event the wrong
value is input.

Since the option to ignore blank cells is unchecked, we assumed that
deleting the proper value from the cell (blank cell) would generate a
validation error message, but it does not. How do we get validation to
alert us when a valid value has been deleted from a cell?