Colin,

Is it possible that this is a second instance of the same form? If so unless you are using the LINKED option you don't have access to a memvar that holds the reference to the form. For example

do form xyz && now a memvar xyz exists, move the form
do form xyz && second form starts, but no new memvar is created
xyz,Release() && the second form goes away, first form is still there

It's more typical to use the _screen.Forms[] collection to release forms enmasse.

for i = _screen.FormCount to 1 step -1
   if ( _screen.Forms[i].QueryUnload() )
      _screen.Forms[i].Release()
   endif
endfor

>I have just noticed that the object cannot be found - but when I look at the list of open windows the form is there.