Thanks for your responses. I used Wipe free space (3 passes on perhaps 10GB of free space) and I didn't use 'close program after use'. It didn't seem to have that option by error as I repeated the wipe later and it took its time to complete although a seemingly shorter time than I waited before bed! The version is 3.28.1913 downloaded from Piriform a few days ago. Perhaps this glitch is just one of those things but if it happened after many hours of a multi- pass it would be annoying.
I ran CCleaner late at night (without any other thing running) and it was taking a very long time so I let it run and went to bed assuming the analysis would be there in the morning. I found only the Desktop showing with no sign of CCleaner anywhere. Does this mean that after analyzing and then no action taken for some time it just closes down? My normal use works fine. Any advice please - thanks. XP Home SP3