> Oops I posted this suggestion to the wrong thread last week...blush
>
> So .....
>
> I have no ideas Peter but it might be useful switch on keystroke
> logging by adding /KBR to the startup command line string to see if it
> something within ztreewin.exe

Thanks, but I'm not sure how something I do in Ztree could affect an Explorer window. As I mentioned, I saw it happen to two Explorer windows simultaneously once.

It's truly strange, and I've never seen it before or since.