I'm a self-employed software developer in the US, using Windows 10 64-bit. I keep the OS updated with the latest patches.

I have hundreds of thousands of small files on my PC, and last week suddenly noticed a huge performance hit, for example when archiving the files using Rar or Zip.

I traced this to Windows Defender real-time file scanning, and such scanning occurs when an existing file is simply opened for reading.

Since I noticed this, I have tried to disable real-time scanning, using the techniques described by Shawn Brink on this forum. This includes making use of the group policy editor with Administrator privileges.

It's easy to temporarily disable the scanning, but it always comes back after a few hours.

So I'm wondering if there's a way to permanently disable the scanning, short of replacing Windows Defender with some other security software.

I'm also wondering why the behavior suddenly changed on me, after using Windows 10 for several years.