ArcMap's Add Data dialog box lists files and directories in descending alphabetical order. Instructions provided describe how to list the contents in ascending order.
The sorting order has been changed in either ArcCatalog or ArcMap. The ArcCatalog tree and ArcMap's Add Data dialog box are the same; therefore, changes made to one are reflected in the other.
The first time the column heading is clicked, its values are sorted in one order. Click the column heading again to reverse the order.