It could be placed in Lostfocus, too

>Sorry but I pressed the wrong key before a finished...
>
>Try this...
>

If This.llunique = .T.
     Set exact on
     if SEEK(this.value,this.lctablethis.lcindex,)
            =Messagebox("&lcvalue allready exist on the table",16,"Opps...")
        NODEFAULT && this will keep focus in the texbox
     Endif
     Set exact off
Endif

>...but I think it should be in the Valid event of the textbox if you want to keep the focus on the textbox.
>
>
>Paco Calvente.