Blank screen after locking screen

Question

I just updated my Xubuntu 14.10 desktop to 15.04 and I'm having the following issue:

When I lock my computer (or when the inactivity timer locks it for me), the screen goes blank and I cannot get into my session. The power light on the monitor is still green which means that the monitor hasn't gone to sleep - i.e. that there is still a video signal but no picture is being sent. The only way to get back into the desktop environment is to switch to a text terminal (Ctrl+Alt+F1) and reboot.

I found a known issue about black screens after boot, but that's not my problem.

I searched through the syslog, but could not find any messages that seem to be related.

I have all the latest packages available via apt-get upgrade.

How can I troubleshoot and fix this issue?

Solution

I had the same problem. I fixed it by going into Light Locker Settings (not sure what it's called: I'm in Windows) and resetting the lockscreen option (turning it off then on again).

Comments

[Moshe Katz]

I also just discovered that I can shorten the wait time by only doing sudo killall Xorg instead of a full reboot, but that still doesn't solve the problem.

[Tim]

please edit that comment in.

[Moshe Katz]

@Tim as far as I'm concerned, it's inconsequential; just a shortcut to not need a full reboot.

[TheWanderer]

Check your screensaver settings. I has this in Kubuntu and resetting the screensaver to something fixed the lock screen for me.

[Moshe Katz]

@Zacharee1 Disabling and reenabling the screen locker has fixed the problem. If you write your comment as an answer, I'll accept it.

[TheWanderer]

Done. (stupid character requirement)

[Moshe Katz]

In Xubuntu 14.04, it's called "Light Locker Settings", and all you have to do is turn it off and on again.

[Unique]

For me, resetting the lock screen option did not work. I installed the "xscreensaver" from software center and it solved the problem.

[stragu]

Looks like this is what described on the Xubuntu website: xubuntu.org/news/… I just had the same issue on a fresh install of Ubuntu Studio 18.04 (which uses Xfce). Interestingly, I had to first install the Light Locker Settings application from Software, and even though it said "Your screensaver settings are managed by Xfce Power Manager", turning "Enable light-locker" off and then on did fix it.