I'm not sure from which version of mame this problem happens.
At least 0.222 version has no problem, but 0.233 or 0.234 version has obviously this problem.
mame.ini file is normally created and saved in ini folder.
But individual game"s ini file is created and saved in mame root folder even though the game's ini file was already in ini folder.
Consequently, if you played ten games, then you will find there are ten ini files in mame root folder!
Does anybody know how to solve this problem?