I have a PC running Win7 that I want to sleep overnight (it is in a bedroom) - however having rescheduled the many many default tasks (why so many???) that are scheduled to run overnight - the Defender disk scan task reverts back to running at 2:30AM after every Defender update.This is such a pain that I have disable auto updates and only update once per week, reboot, and then edit the task Scheduler to move the disk scan back to 1:30PM when the PC will be idle.Any ideas , suggestions - even how to delete Defender is looking like a good option now.regardsSteve

Hi,After turning on Windows Defender, please clear the "Run a scan only when system is idle" option in Tools Properties. Also, please set an approximate time which you would like to run scan. Does the issue persist now? If the issue persists, I suggest you stop Windows Defender service and restart it again. (To verify Windows Defender service, you can click Start menu and type "Services.msc" in Search box, and then press Enter.)Thanks,Novak

If you do not have it, Microsoft's free Security Essentials obviates need for Defender, { Download http://www.microsoft.com/Security_Essentials/ } is more user controllable and will/does replace the need for 3rd party software like Norton etc.

Hi Novak,Yes that is already set - I have done as you suggest and will await the overnight result.thanksSteve

HiThanks for that tip - I prefer to use AV software and malware scanner software from different sources and as MS write the operating system that precludes using there AV software.I do the same in the office server AV is different to desktop AV - increases the odds that if one set misses it the other will get it.thanks againSteve