Note sure I understand well, but from what I see, perhaps you should add a 'checked to true' condition:
Code:
Sub Checkobratodas_CheckedChange(Checked As Boolean)
if checked then
Checkobrasfinalizadas.checked=false
Checkobraspendientes.checked=False
end if
End Sub
Sub Checkobrasfinalizadas_CheckedChange(Checked As Boolean)
if checked then
Checkobratodas.Checked=False
Checkobraspendientes.checked=False
end if
End Sub
Sub Checkobraspendientes_CheckedChange(Checked As Boolean)
if checked then
Checkobratodas.checked=False
Checkobrasfinalizadas.checked=False
end if
End Sub