Because full scans were taking so long, I created a custom scan so that only new or changed files would be scanned. (Inconveniently, that option is no longer available on standard full scans.) Even so, scans are taking more than three hours uninterrupted on my Windows 8 computer that has less than 80 GB of programs and data. My memory is that full scans used to be much faster on this same machine, so I don't think it's due to processor speed. Any idea why - or what I can do to speed things up?