Can one prevent Antimalware Executable to start hogging CPU for extended periods each time some network adapter gets active?

I have admin rights on my Win8 pc, and in the Task Scheduler **Library/Microsoft/Windows/Windows defender,**the condition "Power" has a checkmark but it is greyed out so I cannot remove the checkmark. how to "ungrey" this condition ?

The lower pane of the main Task Scheduler window is inactive. In order to edit the conditions for any task you need to right-click on the task and select “Properties”, or double-click on the task. However, unchecking the items in the conditions tab won’t prevent the Windows Defender Scheduled Scan from running, as I’ve already mentioned. Automatic Maintenance runs the Windows Defender Scheduled Scan task daily, and there are quite a few reports of it failing to yield to user activity, as it should do in its default mode. Here are a few things you can try if the Windows Defender scan doesn't stop whenever you start using your computer:

1.) Uninstall any other potentially conflicting (real-time) AV products. The most common cause of excessive CPU utilization and scan times is a conflicting AV product, although this same excessive-workload issue can also be caused by third-party monitoring or logging utilities.

2.) Reschedule Automatic Maintenance (in the Action Center) for a time when the PC will be on but not in use.

3. While it’s generally not a good Idea to modify the Windows Defender Scheduled Scan task, there’s a report here (by Rob Sherratt) that enabling the idle condition might be a workaround for this issue:

http://answers.microsoft.com/en-us/windows/forum/windows\_8-performance/windows-defender-windows-8-schedule-option-missing/b6603c6a-cba9-4ba7-a894-37f895fc6c92

4.) Disable the Windows Defender Scheduled Scan task by right-clicking on the task and selecting “Disable”.

5.) Install a third-party AV product; which should disable Windows Defender.

GreginMich

I have the 4 tasks and an additional task I created that updates the signature files every 6 hours. For ALL tasks I left the IDLE, POWER and NETWORK as they were and on the first tab (labeled General) I unchecked Run with highest privileges.

I am now able to walk up to my PC anytime and use it without the Antimalware Service Executable (Windows Defender) taking over my CPU (80-95%) and NOT yielding it to back to me until it feels like it ... usually 10-15 minutes. I also run MalwareBytesPro which installs itself to be run at normal priority.

It was set to run only after being idle for 10 minutes but that did not seem to stop the tasks.

I can confirm that "Antimalware Service Executable" eats an entire CPU core every time I boot my PC, whether it's a cold boot or not makes no difference. What's worse is this causes delays during Windows Startup that create a horrible user experience.

This is not the experience I am accustomed to and feel something has changed in recent years.

I certainly do not blame Windows 8, since if I intentionally damage the binaries for this process I no longer experience a problem.

It doesn't matter what scheduled tasks settings are set to. The solutions provided in this post, although very informative, do not address the problem users experience.

Microsoft needs to re-evaluate this product or yank it from the stack. Keeping this in the mix with these kinds of issues will only serve to sully their brand further.

For reference I have a quad core extreme with an SSD and this process still manages to destroy boot times, luckily I only have to wait 2 minutes or so. I can only imagine the pain lower end users are experiencing.

I had exactly the same problem and I followed the

steps you gave, but my computer won't let me uncheck

the boxes, what should I do?