Having Googled the problem and followed the various suggestions, I STILL lack an effective method. A site that had 'microsoft' in the address line gave the following advice : "S.V.I. can and should be deleted from USB flash drives, it has no place on them. There is a way to prevent its creation that appears to have no other adverse effects. Right click "Computer", select "Manage", double click "Services and Applications", then single click "Services". In the right pane, scroll down and find "Storage Service". Right click, and select "Properties". If it is running, click the "Stop" button. Then in the dropdown labelled "Startup Type:" select "Disabled" This will prevent the unnecessary storage service from running, since it is responsible for creating S.V.I. on USB drives." Below it was an option to say whether that was useful or not. I chose the NOT option, but when I shut it down and reopened it later, it ONLY had '7 found this useful'. I am still looking for an effective method.- can anyone help ?