Microsoft Defender exclusions for game folders: do they fix stutter, and are they safe?

Defender scans files as a game opens them, which can stall loading and shader compilation. An exclusion tells it to skip a folder or program. This tweak adds exclusions for the Steam and Riot Games folders it finds and for common launcher programs.

In the app the switch is called "Defender Performance Exclusions", described there as: Adds AV exclusions for common launchers/games to prevent scan stalls.

Exactly what the switch changes, read from the app's source. Switching it off is what the app writes when you turn the tweak off again.

This tweak has no fixed list of registry values to print here: it works through a driver's own settings, scheduled tasks or values that differ from PC to PC (per device, per adapter or per installed game). The app reads what your PC has and changes only that.

Switch the tweak off in Frozen Tweaks.

Changing several settings at once? The app's Make a restore point button, on every plan, makes a Windows restore point before you start.

Effective when Defender is the cause, with a real security cost. Keep downloads and mods out of excluded folders.

Is "Defender Performance Exclusions" safe to switch on?

Effective when Defender is the cause, with a real security cost. Keep downloads and mods out of excluded folders. The main cost: Files in excluded folders are not scanned, so a malicious file placed there would not be caught. Mods and downloads from unknown sources are the usual way that happens.

How do I undo it?

Switch the tweak off in Frozen Tweaks. Switching it off sets a standard Windows value, which may not be exactly how you had it.

Is "Defender Performance Exclusions" free in Frozen Tweaks?

It is part of Frozen Pro and Elite. You can also make the change by hand with the values on this page.