How do I get the Minecraft GUI scale to go back to Auto?

I have been playing Minecraft, and I went into the settings to see what could be changed. I was in display and I saw the GUI scale was set to "Auto", which was fairly large. I cycled through the scales until I got back to auto, but the GUI scale was stuck at normal size and wouldn't allow me to make it large again. I know this isn't such a big problem, but I really like big font and this is a constant bother to me.

Solution 1:

In all tests simply putting my Minecraft window to fullscreen and then changing the GUI mode in the options allows me to have large buttons and font with a fullscreen minecraft.

I have tried both older and the most updated stable released version of minecraft. (no snapshots)

If this does not work for you for some reason my assumption would be your either doing it wrong unawares, or there is something wrong with your files.

Solution 2:

Simple fix for this. Go into the minecraft folder and delete the settings.txt file. Restart minecraft and it'll be back to normal.