Prompted by all the upowerd errors in syslog, I tried to run it manually...
[~]$ gnome-settings-daemon --replace (gnome-settings-daemon:8495): libupower-glib-WARNING **: Couldn't connect to proxy: Error calling StartServiceByName for org.freedesktop.UPower: GDBus.Error:org.freedesktop.DBus.Error.TimedOut: Failed to activate service 'org.freedesktop.UPower': timed out Segmentation fault (core dumped) 25000 May 4 11:00:04 mwaterm1-x250 upowerd[8572]: /usr/lib/upower/upowerd: error while loading shared libraries: libusbmuxd.so.2: cannot open shared object file: No such file or directory 25001 May 4 11:00:04 mwaterm1-x250 systemd[1]: upower.service: Main process exited, code=exited, status=127/n/a 25002 May 4 11:00:04 mwaterm1-x250 systemd[1]: Failed to start Daemon for power management. 25003 May 4 11:00:04 mwaterm1-x250 systemd[1]: upower.service: Unit entered failed state. 25004 May 4 11:00:04 mwaterm1-x250 systemd[1]: upower.service: Failed with result 'exit-code'. 25005 May 4 11:00:04 mwaterm1-x250 systemd[1]: upower.service: Service hold-off time over, scheduling restart. 25006 May 4 11:00:04 mwaterm1-x250 systemd[1]: Stopped Daemon for power management. 25007 May 4 11:00:04 mwaterm1-x250 systemd[1]: Starting Daemon for power management... 25008 May 4 11:00:04 mwaterm1-x250 upowerd[8574]: /usr/lib/upower/upowerd: error while loading shared libraries: libusbmuxd.so.2: cannot open shared object file: No such file or directory Since that file isn't found, I figured I'd try to link it just like the libusbmuxd.so.4 (which is installed) to libusbmuxd.so.4.0.0 $ sudo ln -s /usr/lib/x86_64-linux-gnu/libusbmuxd.so.4.0.0 /usr/lib/x86_64-linux-gnu/libusbmuxd.so.2 and that fixed this error so I can now use the 'Screen Display' tool again - ie the 'Apply' button actually works now. It seems to me like a few binaries are still linked to libusbmuxd.so.2 instead of .4, and they need rebuilding. However, the 'Screen Display' tool doesn't register all three monitors I have connected...I presume that is a different problem. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1577760 Title: Screen Display 'Apply' fails To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/1577760/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs