When creating a layer from x and y coordinates, ArcMap crashes if the table has no rows. Similarly, ArcMap crashes if the first row has null values for the x and y coordinates.
The layer was created before adding the date. The table must contain data and the X and Y fields for the first row must not be null.
Make sure the table used to define the layer has at least one row and the first row in the table must not have null X and Y values. Other rows may have null X and Y values.