Comment 14 for bug 1471254

I'm having the same issue on one of my laptops. mate-settings-daemon often fails to start with this same error message. I've tried altering the "serial" field in ~/.config/monitors.xml to be non-zero, and I've also tried just removing that file and restarting or logout/login. No effect, same error persists for me.

It seems tied to the video driver also. mate-settings-daemon never fails to start when I have the nvidia prime profile set to use only Intel integrated GPU (low-power mode), but when I put it into NVIDIA (performance-mode), then it alwasy fails to start.

It's also tied to multi-monitor setup. If I start in multi-monitor display mode with the external hdmi already connected, mate-settings-daemon fails to start. I have discovered, now, if I start the laptop with NVIDIA performance enabled, but the external HDMI *NOT* connected, then mate-settings-daemon starts. Once the system is started and I'm logged in and themes are applied properly, I can THEN attach the external HDMI cable and it will recognize the second monitor, turn it on, and I get my styles on the second monitor, in NVIDIA perfomance mode, which is the goal.

So, the monitors.xml file definitely seems related, and it seems clear the failure has to do the allocation of video to separate monitors, or just an external monitor. I believe there is some fail case in mate-settings-daemon that is not gracefully handled or reported, but I don't have time to dig through that code and debug the video/monitor output allocation logic.