This is 2nd query - I put the earlier one on your blog and now realize this is the appropriate venue.
Updated WP SC yesterday and clicked a couple of "recommended" boxes. After today's post came due visitors to the site got "This site wants to send you a zipped file, accept?" Deactivating SC fixed the issue. I then reactivated it without checking anything. My site still worked fine but there were a few "warning ..." messages at the top of the SC admin page. Strangely, these disappeared when I deactivated and reactivated. But I now have a warning that there are lines in my .htaccess that reference Super Cache and that these should be addressed. These lines ARE there and were added a long time back as part of getting Super Cache operational. Is it the case now that all Super Cache entries in my .htaccess should be deleted? Or should I perhaps deactivate Super Cache and then reinstall fresh?