The method for returning back to default values doesn't work anymore because the new Skyrim.ini, generated through 'saveini', is now saved in the data folder. When I copy this file into my 'My Documents/My Games/Skyrim'-direction it doesn't work and I get a CTD while loading the savegame.
Is there any other method for returning back to default?
Use the "refreshini" command without quotes.
1) Load save game while using appropriate UGridsToLoad setting to successfully load it.
2) Alt-Tab out of the game and open Skyrim.ini
3) Revert UGridsToLoad setting to a lower/preferred value
4) Alt-Tab back to game and open the console, type "refreshini" without quotes
5) Save game
6) Exit game to desktop
7) Start the game and load your save game
If you skip step 6 and attempt to load the save game then the game will crash, the process has still succeeded though so you should be able to load your latest save game with the new UGridsToLoad values in effect.