My question is a duplicate of this but I would like to keep it here because I did not find the other question when searching for a solution.
I am not able to log into the Lubuntu session from the graphical login screen. I have login without password enabled and if I click on login it simply throws me back to this login page after 2 seconds of black screen.
I run a ZOTAC mini PC with Lubuntu 16 on it. I know it is EOL. It was running fine and I was accessing it via VNC from a Mac. It was running Mediathekview which is a graphical software to download TV content. It was connected to my Raspberry Pi's external HDD via samba so that it downloaded everything onto this HDD in the LAN.
My RPi crashed (sd card failure) and it seemed that the ZOTAC also had a crash because I could not close the filemanager. I never experienced this. I was thinking about the possibility that the download went on and my local HDD inside the ZOTAC got full. But this is not the case as du shows only 22GB.
Before I realized that I could not log in with a monitor and mouse attached I was just trying to log into VNC from a Mac and then on terminal trying to find out if VNC was maybe down. I was not able to telnet 127.0.0.1 6000 and then attached a monitor to check what was going on.
I also tried to start xserver from the terminal when logged in via SSH and I am not sure if this maybe also messed up things. But I am pretty sure that the problem with the login was like this from the start.
I also tried to sudo apt install lubuntu-desktop and while I would have been expecting that this was already installed it was not and so I installed it (again). Now I have several options of graphical environments to log into: LXDE, Lubuntu, Ubuntu and Openbox but none of them work.
top looks like this. I think java indicates that Mediathekview is running and the MongoDB might be from a router management software. So there seem to be running things that only get started when I log into the system.
PID USER PR NI VIRT RES SHR S %CPU %MEM ZEIT+ BEFEHL
24 root 20 0 0 0 0 S 0,3 0,0 0:00.01 kworker/3:0
953 mongodb 20 0 388324 48624 18216 S 0,3 1,3 0:00.18 mongod
1483 ntp 20 0 112096 5032 4412 S 0,3 0,1 0:00.02 ntpd
1573 root 20 0 3545512 73280 19248 S 0,3 2,0 0:01.31 launcher
1783 root 20 0 4631872 167540 22152 S 0,3 4,6 0:05.29 java
2620 ben 20 0 43604 4052 3276 R 0,3 0,1 0:00.01 top
1 root 20 0 120096 6308 4064 S 0,0 0,2 0:01.17 systemd
2 root 20 0 0 0 0 S 0,0 0,0 0:00.00 kthreadd
3 root 20 0 0 0 0 S 0,0 0,0 0:00.00 ksoftirqd/0
4 root 20 0 0 0 0 S 0,0 0,0 0:00.00 kworker/0:0
5 root 0 -20 0 0 0 S 0,0 0,0 0:00.00 kworker/0:0H
6 root 20 0 0 0 0 S 0,0 0,0 0:00.00 kworker/u8:0
7 root 20 0 0 0 0 S 0,0 0,0 0:00.04 rcu_sched
8 root 20 0 0 0 0 S 0,0 0,0 0:00.00 rcu_bh
9 root rt 0 0 0 0 S 0,0 0,0 0:00.00 migration/0
10 root rt 0 0 0 0 S 0,0 0,0 0:00.00 watchdog/0
11 root rt 0 0 0 0 S 0,0 0,0 0:00.00 watchdog/1
12 root rt 0 0 0 0 S 0,0 0,0 0:00.00 migration/1
13 root 20 0 0 0 0 S 0,0 0,0 0:00.00 ksoftirqd/1
14 root 20 0 0 0 0 S 0,0 0,0 0:00.00 kworker/1:0
15 root 0 -20 0 0 0 S 0,0 0,0 0:00.00 kworker/1:0H
16 root rt 0 0 0 0 S 0,0 0,0 0:00.00 watchdog/2
17 root rt 0 0 0 0 S 0,0 0,0 0:00.00 migration/2
18 root 20 0 0 0 0 S 0,0 0,0 0:00.00 ksoftirqd/2
19 root 20 0 0 0 0 S 0,0 0,0 0:00.00 kworker/2:0
20 root 0 -20 0 0 0 S 0,0 0,0 0:00.00 kworker/2:0H
21 root rt 0 0 0 0 S 0,0 0,0 0:00.00 watchdog/3
22 root rt 0 0 0 0 S 0,0 0,0 0:00.00 migration/3
23 root 20 0 0 0 0 S 0,0 0,0 0:00.00 ksoftirqd/3
25 root 0 -20 0 0 0 S 0,0 0,0 0:00.00 kworker/3:0H
26 root 20 0 0 0 0 S 0,0 0,0 0:00.00 kdevtmpfs
27 root 0 -20 0 0 0 S 0,0 0,0 0:00.00 netns
28 root 0 -20 0 0 0 S 0,0 0,0 0:00.00 perf
29 root 20 0 0 0 0 S 0,0 0,0 0:00.00 khungtaskd
30 root 0 -20 0 0 0 S 0,0 0,0 0:00.00 writeback
.xsession-errors is:
openConnection: connect: Datei oder Verzeichnis nicht gefunden
cannot connect to brltty at :0
upstart: window-stack-bridge-main-Prozess (6441) wurde von HUP-Signal beendet
upstart: bamfdaemon-main-Prozess (6482) wurde von TERM-Signal beendet
upstart: lxsession-main-Prozess (6565) wurde von TERM-Signal beendet
upstart: Vom benachrichtigten D-Bus-Bus getrennt
Xsession: X session started for root at Di 3. Sep 16:49:50 CEST 2019
localuser:root being added to access control list
openConnection: connect: Datei oder Verzeichnis nicht gefunden
cannot connect to brltty at :0
lubuntu-desktopisn't a big deal. It can be removed if you uninstall certain packages specified by it. – DK Bose Sep 03 '19 at 15:42