Comment #35 on issue 97 by s.g.mcat...@gmail.com: xmonad stops responding to keyboard input after running xscreensaver http://code.google.com/p/xmonad/issues/detail?id=97 I also had this issue and it turned out that I somehow had two copies of the xscreensaver daemon running at startup. To check if this is the case in your configuration, open a terminal and type: $ ps aux | grep xscreensaver You should get something like: ******** 970 0.7 0.0 59528 2836 ? S 07:06 0:00 xscreensaver -nosplash ******** 1050 0.0 0.0 9144 1060 pts/1 S+ 07:06 0:00 grep --color=auto screen The top line is the xscreensaver daemon and the second line is the command you entered above - this is what it *should* look like. When I had two copies of xscreensaver running, i.e. the output looked like: ******** 970 0.7 0.0 59528 2836 ? S 07:06 0:00 xscreensaver -nosplash ******** 970 0.7 0.0 59528 2836 ? S 07:06 0:00 xscreensaver -nosplash ******** 1050 0.0 0.0 9144 1060 pts/1 S+ 07:06 0:00 grep --color=auto screen I was suffering the described error. Solution: check your startup scripts to make sure that xscreensaver daemon is only launched once.