For those having trouble, try removing the ".txt" part of the file name.
So instead of "platformsettings.txt" it should be: "platformsettings"
If you save a file from Notepad itself, and append the ".txt", it will automatically be removed from the file name as the file type already is a text file. However, this only works when saving from Notepad. If you rename a file in Window's Explorer and append the ".txt" it will not automatically remove it. So the file name will be "platformsettings.txt.txt".