我尝试升级，但出现错误。这是输出的尾部
Import process completed.
Done
done.
Processing triggers for libgdk-pixbuf2.0-0:amd64 (2.32.2-1ubuntu1.2) ...
Processing triggers for ureadahead (0.100.0-19) ...
Processing triggers for dbus (1.10.6-1ubuntu3.1) ...
Processing triggers for resolvconf (1.78ubuntu2) ...
Processing triggers for vlc-nox (2.2.2-5) ...
Processing triggers for bamfdaemon (0.5.3~bzr0+16.04.20160824-0ubuntu1) ...
Rebuilding /usr/share/applications/bamf-2.index...
Errors were encountered while processing:
emacs24
emacs
Error in function:
Could not install the upgrades
The upgrade has aborted. Your system could be in an unusable state. A
recovery will run now (dpkg --configure -a).
Setting up emacs24 (24.5+1-6ubuntu1) ...
Install cmake-data for emacs24
install/cmake-data: Byte-compiling for emacs24
emacs24: relocation error: /usr/lib/x86_64-linux-gnu/libboost_system.so.1.58.0: symbol _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED1Ev, version GLIBCXX_3.4.21 not defined in file libstdc++.so.6 with link time reference
Install emacsen-common for emacs24
emacsen-common: Handling install of emacsen flavor emacs24
emacs24: relocation error: /usr/lib/x86_64-linux-gnu/libboost_system.so.1.58.0: symbol _ZNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEED1Ev, version GLIBCXX_3.4.21 not defined in file libstdc++.so.6 with link time reference
ERROR: install script from emacsen-common package failed
dpkg: error processing package emacs24 (--configure):
subprocess installed post-installation script returned error exit status 1
dpkg: dependency problems prevent configuration of emacs:
emacs depends on emacs24 | emacs24-lucid | emacs24-nox; however:
Package emacs24 is not configured yet.
Package emacs24-lucid is not installed.
Package emacs24-nox is not installed.
dpkg: error processing package emacs (--configure):
dependency problems - leaving unconfigured
Errors were encountered while processing:
emacs24
emacs
Upgrade complete
The upgrade has completed but there were errors during the upgrade
process.
To continue please press [ENTER]
我重新启动了，现在系统无法启动。它发布了一条消息
/dev/sda6: clean, 645654/20442624 files, 21700419/113769472 blocks
并且屏幕持续轻微闪烁。关于如何恢复启动，您有什么想法吗？
我知道一个选项是重新安装。这是 从 ISO 安装 Ubuntu...无法安装 grub
答案1
您可以尝试从 grub 菜单启动到较旧的内核。启动时按住 Shift 键应该会显示 grub 启动菜单。
希望您能看到作为升级的一部分安装的较新的内核以及可以启动的较旧的内核版本。
如果可以选择较旧的内核，则启动它。然后，您可以尝试使用以下方法修复任何损坏的软件包：
sudo apt-get -f install
根据以往的经验，如果升级过程中出现问题，我通常会放弃并进行全新安装。事实上，当我从 14.04 升级到 16.04 时，我只是选择了全新安装选项。您可能能够察觉并修复启动问题，但会发现存在其他问题，并且您可能花费比修复它们更多的时间。
最坏的情况（也可能是最简单的选择）我建议使用实时 CD 进行启动并将所有文件保存到 USB 驱动器上，然后进行全新安装。