Auto Upper Case Problems

I am using the code below to force everything to upper case

Please Login or Register  to view this content.

Works fine until i wast to copy a cell by dragging down, then i get this

Run Time Error 13
Type Mismatch

Is there a way to force upper case and allow me to copy from say a1 to a2:a20

Thanks

Graham

Please Login or Register  to view this content.

Testing before upper-casing preserves Undo if no changes are necessary.