Thanks MilesAhead.
I am not sure to what you are referring since the computer didn't actually crash and there are no detectable performance issues.
However, since I am running such a fast processor with so much RAM, issues might not be visible in the way I am use to them manifesting (i.e. slow downs etc.)
The fact that there was an error message, which was supressed during half a dozen shutdowns, then only the final message before the update requiring any action on my part, perhaps indicates it was a minor issue. I wanted to be sure, hence my post.
Can someone help me identify from the screen shots which might be the message that generated the error report?