Ubuntu 18.04 统一登录循环

问题说明：

4.15.0-46-generic x86_64 GNU/Linux当我尝试使用“Unity（默认）”（安装在：https : //linuxconfig.org/how-to-install-unity-desktop-on -ubuntu-18-04-bionic-beaver-linux）。在从第三方 PPA（nextgis：https ://launchpad.net/~nextgis/+archive/ubuntu/ppa?field.series_filter=bionic ）安装/弄乱 libprotobuf10/15 之前，一切都很好。

我试过的：

这里的答案都没有帮助：Ubuntu陷入登录循环

显卡驱动：

我没有任何第三方图形驱动程序，例如 NVidia 或 AMD；

$ sudo lshw -c video
  *-display                 
       description: VGA compatible controller
       product: HD Graphics 5500
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 09
       width: 64 bits
       clock: 33MHz
       capabilities: msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:45 memory:f0000000-f0ffffff memory:e0000000-efffffff ioport:3000(size=64) memory:c0000-dffff

我做了什么：

我认为python3-protobuf从nextgisPPA 安装后统一已损坏：libprotobuf15 install prompt for remove system packages但在停用此 PPAapt-get update并重新安装后ubuntu-unity-desktop，官方python3-protobuf问题仍然存在；

$ sudo apt-cache policy ubuntu-unity-desktop
ubuntu-unity-desktop:
  Installed: 0.1
  Candidate: 0.1
  Version table:
 *** 0.1 500
        500 http://ch.archive.ubuntu.com/ubuntu bionic/universe amd64 Packages
        100 /var/lib/dpkg/status

$ sudo apt-cache policy python3-protobuf
python3-protobuf:
  Installed: 3.0.0-9.1ubuntu1
  Candidate: 3.0.0-9.1ubuntu1
  Version table:
 *** 3.0.0-9.1ubuntu1 500
        500 http://ch.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
        100 /var/lib/dpkg/status

我还尝试删除.Xauthority并.ICEauthority重新配置lightdm：

$ sudo dpkg-reconfigure lightdm    

但他们都没有工作。

我准确地说我可以毫无问题地使用 gnome 登录，但是在统一后，我的屏幕会在几秒钟内变黑，然后我再次面对会话登录屏幕。

问题：

如何恢复统一会话？

更多信息：

这可能会有所帮助：

文件的最后一行.xsession-errors：

A dependency job for unity-session.target failed. See 'journalctl -xe' for details.

journalctl -xe我在使用统一登录后运行的命令输出中的这些行可能告诉我们lightdm身份验证有问题：

mar 25 11:26:57 username-laptop-1804 lightdm[5441]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory
mar 25 11:26:57 username-laptop-1804 lightdm[5441]: PAM adding faulty module: pam_kwallet.so
mar 25 11:26:57 username-laptop-1804 lightdm[5441]: PAM unable to dlopen(pam_kwallet5.so): /lib/security/pam_kwallet5.so: cannot open shared object file: No such file or directory
mar 25 11:26:57 username-laptop-1804 lightdm[5441]: PAM adding faulty module: pam_kwallet5.so
mar 25 11:26:57 username-laptop-1804 lightdm[5441]: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "username"
mar 25 11:27:02 username-laptop-1804 systemd-logind[776]: Removed session c6.
-- Subject: Session c6 has been terminated

dmesg1 次统一登录失败后 的一些输出：

$ dmesg | grep -i "warn\|err\|lightdm\|unity"
[    0.000000] ACPI: IRQ0 used by override.
[    0.000000] ACPI: IRQ9 used by override.
[    0.045146] ACPI: EC: interrupt blocked
[    0.061268] ACPI Error: Needed type [Reference], found [Integer]         (ptrval) (20170831/exresop-103)
[    0.061300] ACPI Error: Method parse/execution failed \_PR.CPU0._PDC, AE_AML_OPERAND_TYPE (20170831/psparse-550)
[    0.063508] ACPI: Using IOAPIC for interrupt routing
[    0.072809] ACPI: PCI Interrupt Link [LNKA] (IRQs 3 4 5 6 7 9 10 *11)
[    0.072923] ACPI: PCI Interrupt Link [LNKB] (IRQs 3 4 5 6 7 *9 10 11)
[    0.073033] ACPI: PCI Interrupt Link [LNKC] (IRQs 3 4 5 6 7 9 *10 11)
[    0.073143] ACPI: PCI Interrupt Link [LNKD] (IRQs 3 4 5 *6 7 9 10 11)
[    0.073252] ACPI: PCI Interrupt Link [LNKE] (IRQs 3 4 5 6 7 9 10 *11)
[    0.073334] ACPI: PCI Interrupt Link [LNKF] (IRQs 3 4 5 6 7 9 10 11) *0, disabled.
[    0.073444] ACPI: PCI Interrupt Link [LNKG] (IRQs 3 4 5 6 7 9 *10 11)
[    0.073553] ACPI: PCI Interrupt Link [LNKH] (IRQs 3 4 5 6 *7 9 10 11)
[    0.101434] ACPI: EC: interrupt unblocked
[    3.588547] RAS: Correctable Errors collector initialized.
[    6.937212] e1000e 0000:00:19.0: Interrupt Throttling Rate (ints/sec) set to dynamic conservative mode
[   10.673768] EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro
[   10.857401] random: 7 urandom warning(s) missed due to ratelimiting
[   12.282650] audit: type=1400 audit(1553512054.380:10): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/lightdm/lightdm-guest-session" pid=603 comm="apparmor_parser"
[   12.282653] audit: type=1400 audit(1553512054.380:11): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/lightdm/lightdm-guest-session//chromium" pid=603 comm="apparmor_parser"

还有一件事; 尝试登录dmesg 之前$ dmesg > dmesg0.txt的输出（我之前输出）和统一尝试不成功之后（我之后输出）之间的输出没有区别$ dmesg > dmesg1.txt。
然后;

$ diff dmesg0.txt dmesg1.txt     

没有给我额外的信息。

还有一条信息；unity --debug在欢迎程序开始任何会话之前从 CLI 运行命令的结果：

/usr/lib/x86_64-linux-gnu/unity/compiz-config-profile-setter: error while loading shared libraries: libprotobuf.so.10: cannot open shared object file: No such file or directory
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
/usr/bin/compiz (core) - Info: Loading plugin: core
/usr/bin/compiz (core) - Info: Starting plugin: core
[New Thread 0x7ffff3118700 (LWP 12410)]
Invalid MIT-MAGIC-COOKIE-1 key/usr/bin/compiz (core) - Fatal: Couldn't open display :0
/usr/bin/compiz (core) - Info: Stopping plugin: core
/usr/bin/compiz (core) - Info: Unloading plugin: core
[Thread 0x7ffff3118700 (LWP 12410) exited]
[Inferior 1 (process 12406) exited with code 01]
No stack.
WARNING: no DISPLAY variable set, setting it to :0