For example, using File > Revert All Settings, restores settings to the as-installed values except for some.
It will not change the values of (1) the Output folder, (2) Overall > Generic > 'Ignored build' and (3) Overall > User interface > 'Do not show welcome screen'.
Unfortunately, it does make (possibly) unwanted changes, such as (a) reverts to 8 sec the value of Overall > User interface > 'Show splash screen for ...' and (b) changes the Browser mode to 'Normal'. The latter is best set to 'Safe' in builds that don't have XULrunner included.
NOTE: if <Original Folder> is sent to a Preset (its value is a blank) it will not overwrite a specific ouput folder, yet a specific folder in a Preset will overwrite <Original Folder>!
Because of these effects, it is easy to conclude that the settings in MediaCoder are unstable when playing around (changing to different Presets makes the changes!).
Hence, I suggest, a Preset called 'Revert to start', or some such, be created by starting with Revert All Settings and then: (I) set 'Do not show welcome screen' = the build number (no Welcome webpage!), (II) set 'Safe Mode' under Options > Browser mode, if old build without XULrunner (no error when using Firefox 3+) and (III) set 0 sec for 'Show splash screen …' (no Splash screen at start). Then, save as Preset.
In practice, whenever creating a new Preset begin by loading 'Revert to start' and include a specific folder as your choice for Output folder!!
I have tried different values (0, 1, 77, 4399, etc) for 'Ignored build' and it ultimately made no difference for me (builds 4490 and 4399) – the New-build webpage opens every time MC is opened. If such a value works for your build, then include that in the Preset.
The above findings were obtained with the 7z version of build 4399