Hold down [windows key] + [R], and a little pop-up will appear.



Make sure the box says "appdata" then click Ok.

Now you will be in the AppData folder. Click on the folder that says "local."

Scroll all the way down to the folder that says "UNDERTALE" and open it.

Delete EVERY FILE in the UNDERTALE folder. These files contain your saves and settings, so we want to delete these.

Open the game and test it! The game should look just like it did when you first start it up, and the characters will have no memory of what you have done in previous playthroughs, great if you have done Genocide.

If you want to do this for DELTARUNE instead, Just go to the DELTARUNE folder in local, and delete all the files in that. Simple! Hopefully this guide helps. FYI, I did this on a Windows 11, so this may be different for some people.