Following a post by John@Parallels (if I remember correctly) I started to get interested in the contents, and possibly of the edition/configuration xorg.conf. A search in Terminal brought up the following list of xorg.conf files available in my system: ********** /etc/X11/xorg.conf /etc/X11/xorg.conf.1 /etc/X11/xorg.conf.2 /etc/X11/xorg.conf.20080424053505 /etc/X11/xorg.conf.20080424153534 /etc/X11/xorg.conf.20080509081756 /etc/X11/xorg.conf.20080509235708 /etc/X11/xorg.conf.20080603042811 /etc/X11/xorg.conf.20080612065225 /etc/X11/xorg.conf.20080613141044 /etc/X11/xorg.conf.20080621075636 /etc/X11/xorg.conf.20080708083240 /etc/X11/xorg.conf.bak /etc/X11/xorg.conf.failsafe /etc/X11/xorg.conf.prl-backup ******* It seems that the files with a digit or a string of digits after the dot in xorg.conf. are successive files generated by Parallels Tools. Are *all* those files required? Which could or should be erased (rm) Or is it safer not to mess with them? I can see a file named whose path is /etc/X11/xorg.failsafe that could be the "trigger" that makes the system read the "current" configuration? I am familiar with .conf files such as gnupg.conf, gpg-agent.conf and understand that they are read by gpg to function. I am not sure how these xorg.conf files could or should be edited. Thanks for pointing me in the right direction (some kind of HOWTO or Documentation), if the explanation is too long to post here. TIA!