I've posted this question over at the MSE site but thought I'd check in with you good folks to see if you had a thought or two... ...I've noticed that occasionally there is a great disparity in the number of files scanned when using the "Quick Scan" option. Ordinarily it's about 32,000 files (plus or minus). Occasionally it drops to about 9,000 (plus or minus). That's a big change. The scan is ordinarily run every four days. (I may not have rebooted during this period as my habit is to put the system to "sleep" at night rather than shut it down completely.) Does MSE scan only "new" unscanned files or is the program just not operating properly for some unknown reason? System: Windows XP Pro SP 3 Thanks in advance for your time and replies.