Thanks Rod. Should it happen again, I'll give that a go. I finished up having to switch off the RB and restarting it in order to clear the message. As I say it has never happened before. Looks as if I may have inadvertantly altered the screen size so that the cross hasn't been showing when the message came up. Me and computers !
Cheers,
Ian
Edit: Just had another alert message and the small cross at the top right of the box is showing ok therefore everything would now appear to be ok.