无法从16.04升级到18.04，没有真正的错误？

我收到通知，说我的桌面安装有更新，但无法这样做。我看不到真正的错误消息。我已经跑了sudo apt autoremove，sudo apt upgrade而且sudo apt install，它给了0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded。这是我运行时的屏幕do-release-upgrade：

Reading cache

Checking package manager
Reading package lists... Done
Building dependency tree
Reading state information... Done
Hit http://us.archive.ubuntu.com/ubuntu xenial InRelease
Hit http://archive.canonical.com xenial InRelease
Hit http://security.ubuntu.com/ubuntu xenial-security InRelease
Fetched 0 B in 0s (0 B/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done

Restoring original system state

Aborting
Reading package lists... Done
Building dependency tree
Reading state information... Done
=== Command detached from window (Mon Aug 20 20:34:56 2018) ===

这是我的main.log：

2018-08-20 20:34:50,649 INFO Using config files '['./DistUpgrade.cfg.xenial']'
2018-08-20 20:34:50,649 INFO uname information: 'Linux egwene 4.4.0-133-generic #159-Ubuntu SMP Fri Aug 10 07:26:31 UTC 2018 i686'
2018-08-20 20:34:50,862 INFO apt version: '1.2.15ubuntu0.2'
2018-08-20 20:34:50,862 INFO python version: '3.5.2 (default, Nov 23 2017, 16:37:01)
[GCC 5.4.0 20160609]'
2018-08-20 20:34:50,864 INFO release-upgrader version '18.04.24' started
2018-08-20 20:34:50,868 INFO locale: 'en_US' 'UTF-8'
2018-08-20 20:34:51,059 DEBUG Using 'DistUpgradeViewText' view
2018-08-20 20:34:51,111 DEBUG enable dpkg --force-overwrite
2018-08-20 20:34:51,150 DEBUG creating statefile: '/var/log/dist-upgrade/apt-clone_system_state.tar.gz'
2018-08-20 20:34:54,329 DEBUG lsb-release: 'xenial'
2018-08-20 20:34:54,330 DEBUG _pythonSymlinkCheck run
2018-08-20 20:34:54,331 DEBUG openCache()
2018-08-20 20:34:54,332 DEBUG No such plugin directory: ./plugins
2018-08-20 20:34:54,332 DEBUG plugins for condition 'PreCacheOpen' are '[]'
2018-08-20 20:34:54,332 DEBUG plugins for condition 'bionicPreCacheOpen' are '[]'
2018-08-20 20:34:54,332 DEBUG plugins for condition 'from_xenialPreCacheOpen' are '[]'
2018-08-20 20:34:54,333 DEBUG quirks: running PreCacheOpen
2018-08-20 20:34:54,333 DEBUG running Quirks.PreCacheOpen
2018-08-20 20:34:54,721 DEBUG /openCache(), new cache size 56038
2018-08-20 20:34:54,721 DEBUG need_server_mode(): run in 'desktop' mode, (because of pkg 'ubuntu-desktop')
2018-08-20 20:34:54,721 DEBUG checkViewDepends()
2018-08-20 20:34:54,721 DEBUG running doUpdate() (showErrors=False)
2018-08-20 20:34:55,529 DEBUG openCache()
2018-08-20 20:34:55,939 DEBUG /openCache(), new cache size 56038
2018-08-20 20:34:55,940 DEBUG doPostInitialUpdate
2018-08-20 20:34:55,940 DEBUG plugins for condition 'PostInitialUpdate' are '[]'
2018-08-20 20:34:55,940 DEBUG plugins for condition 'bionicPostInitialUpdate' are '[]'
2018-08-20 20:34:55,940 DEBUG plugins for condition 'from_xenialPostInitialUpdate' are '[]'
2018-08-20 20:34:55,940 DEBUG quirks: running bionicPostInitialUpdate
2018-08-20 20:34:55,940 DEBUG running Quirks.bionicPostInitialUpdate
2018-08-20 20:34:55,951 DEBUG abort called
2018-08-20 20:34:55,951 DEBUG openCache()
2018-08-20 20:34:55,951 DEBUG failed to SystemUnLock() (E:Not locked)
2018-08-20 20:34:56,356 DEBUG /openCache(), new cache size 56038

这可能是什么问题？

编辑

使用WinEunuuchs2Unix提供的链接，这是我的PPA链接：

'http://us.archive.ubuntu.com/ubuntu/ xenial main restricted'
'http://us.archive.ubuntu.com/ubuntu/ xenial universe'
'http://us.archive.ubuntu.com/ubuntu/ xenial multiverse'
'http://security.ubuntu.com/ubuntu xenial-security main restricted'
'http://security.ubuntu.com/ubuntu xenial-security universe'
'http://security.ubuntu.com/ubuntu xenial-security multiverse'
'http://archive.canonical.com/ xenial partner'

尝试：

sudo apt-get install lsb-core

然后升级

有时，此软件包已丢失或损坏，并且安装程序很难确定当前正在运行哪个版本。如果您使用Google进行搜索，则会有很多抱怨。在Debian中可能会发生同样的情况。

从17.10开始，Ubuntu已停止支持32位桌面系统。根据https://www.ubuntu.com/download/alternative-downloads，最新版本的32bit是16.04.5 。

哇我真瞎

我想念xenial-updates软件包的源代码。

展开/etc/apt/sources.list

deb http://us.archive.ubuntu.com/ubuntu xenial-updates main restricted universe multiverse

更新xenial

sudo apt update && sudo apt full-upgrade

然后再试一次。如果这不起作用，我就没主意了。

而且您知道备份1。