Is "Purge FSE Shims" safe to switch on?

A cleanup step for a PC with a tweaking history. On a clean install there is nothing to delete. The main cost: It is one-way: if you wanted fullscreen optimizations forced off, you set that again afterwards.

In the app this one is one-way. Purged compatibility flags aren't put back.

Is "Purge FSE Shims" 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.

GameDVR_FSEBehavior and GameDVR_FSEBehaviorMode: clearing the global fullscreen optimization overrides

Frost LIVEWindowsProUndo: One-wayUpdated Oct 8, 2026View as Markdown

Short answer

Updated Oct 8, 2026

GameDVR_FSEBehavior and GameDVR_FSEBehaviorMode under GameConfigStore are global switches that force fullscreen optimizations on or off for every game. Tweak packs often set them and leave them behind. This tweak deletes both values, so Windows and each game decide again.

What it does

In the app the switch is called "Purge FSE Shims", described there as: Removes the stored fullscreen optimization overrides, so games go back to their own fullscreen mode.

When it helps, and when it hurts

When it helps

Cleaning up after old tweak packs when fullscreen behaves oddly: alt-tab problems, wrong refresh rate, capture not working.

When it hurts

It is one-way: if you wanted fullscreen optimizations forced off, you set that again afterwards.
It removes what the Game DVR tweak in this app sets for fullscreen behavior, so use one or the other.

What it writes

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.

Deletes the value GameDVR_FSEBehavior under HKCU\System\GameConfigStore.
Deletes the value GameDVR_FSEBehaviorMode under HKCU\System\GameConfigStore.

How to undo it

In the app: One-way

Purged compatibility flags aren't put back.

This tweak is one-way in the app: switching it off does not put things back. Purged compatibility flags aren't put back.

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

Verdict

A cleanup step for a PC with a tweaking history. On a clean install there is nothing to delete.

Questions

Is "Purge FSE Shims" safe to switch on?: A cleanup step for a PC with a tweaking history. On a clean install there is nothing to delete. The main cost: It is one-way: if you wanted fullscreen optimizations forced off, you set that again afterwards.
How do I undo it?: In the app this one is one-way. Purged compatibility flags aren't put back.
Is "Purge FSE Shims" 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.

In the app