Delay related to Windows Defender

Reading Directory Opus Freezes after First Install prodded me into writing this just for information only because it also involves Windows Defender although I don't have the issue described.

I have a folder containing all my program installation files. The first time I navigate to this folder after a reboot, there is a significant delay before the icons are correctly displayed. I usually notice this when I navigate to this folder with the intention of immediately copying a new file into it. Pressing Ctrl-V (to copy) results in Opus "Not Responding" for a while. After a bit, the icons are properly displayed and the copy takes place.

The issue doesn't have anything to do with copying. Pressing Page Down results in the same delay.

This definitely occurs only when Windows Defender Real-time protection is on and icons are displayed (Details mode).

Those with a long memory may recall my reporting this behavior in the past as related to Microsoft Security Essentials.

It seems to me that I've had times during which the problem doesn't manifest itself during the Security Essentials era but I can't be sure at this point because I've sometimes used Security Essentials/Windows Defender and sometimes not.

For the moment, I'm solving the problem by turning off the display of icons in Details mode.

This is just for information. I'm not expecting anybody to fix anything.

For whatever it's worth, I'm still running Windows 10 and Windows Defender and currently do not have the effect described above. This seems consistent with my recollection regarding Windows 7 and Microsoft Security Essentials that the effect comes and goes randomly.

The icons still display somewhat slowly, but Opus is not "not responding" while waiting for the icons to display.

I'll keep watching this. So far, I'm unable to identify any known factor that might have caused a change in behavior.

Windows Defender always has CPU spikes when confronted with a folder full of .exe files, in both Opus and Explorer. As I too keep a backup of my program installation files, I got around this problem by simply adding a folder exclusion rule under Windows Defender.

Something worth thinking about, I guess, but the point I was trying to make in my last post is that, at least for me, it seems to be "sometimes" rather than "always".