Thanks for your response. In the end, I stopped the scan after 20 hours (2.8million items scanned) and got the 'no threats found' message. In answer to your points, 1) I am using Windows 10 Pro, version 21H1, installed 01/03/21, OS Build 19043.2006. I have no idea how to answer point 2, but it updates itself regularly; last three times at 09:30 this morning, 23:24 and 20.52 last night. Point 3: I recall running one when Kaspersky first installed. Point 4) around a year/18 months ago, from memory. Point 5) wouldn't have a clue how to modify such things - I am not an IT professional - rather a just-retired Financial Services Senior Administrator (I had the luxury of a first class IT department behind me then!) and Point 6: the computer is fully shut down every evening before turning in, and turned on via the power button when next needed.