Loosing prefs

[micheus]

He was happilly using version 1.5.3 for a few weeks now without a problem.
Recently i proposed to him to try the last manifoldlab version so he could use boolean things, he always liked to do that sort of things.
...
I warned him that it could cause bugs with the prefs getting messed.

Next time it's a good idea make a backup of preferences before.

I don't know what to say, but the best way you reset the preferences to its default values and start changing to your desired settings is by removing it (deleting). Wings3d will create a new one as it supposed should be. Maybe this can "fix" the your friend's problem.
You shouldn't need to exit Wings3d for every new settings you change, but - yes - you need exit Wings3d in order to get these changes written to the preferences file.