我安装了 Unity 的 Ubuntu 15.10，然后在一周前尝试安装 gnome 3。一切都运行正常，但一周后，我想我会恢复到 Unity，因为我更喜欢它。
首先，我刚刚注销，选择 Unity，然后再次登录。这样我就进入了 Unity，但有缺陷。顶部面板和侧边栏都在，但没有桌面（因为没有背景图像，桌面上没有项目，尽管我知道那里有一些）
我以为我会卸载 gnome 3，但一定是出了什么问题，因为现在当我进入 unity 时，我有一个背景，但桌面上仍然没有任何东西，每当我尝试连接第二个屏幕时，unity 就会冻结，并且 CPU 会发疯。
我肯定卸载了一些应该保留的软件包和依赖项，但现在我不知道如何让它恢复完全功能
那么有没有办法从头开始重新安装 Unity 或者只是修复它？
sudo apt-get install -f 输出：
~$ sudo apt-get install -f
[sudo] password for mads:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
linux-headers-4.2.0-30 linux-headers-4.2.0-30-generic
linux-image-4.2.0-30-generic linux-image-extra-4.2.0-30-generic
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 12 not upgraded.
并执行 sudo apt-get 检查：
~$ sudo apt-get check
Reading package lists... Done
Building dependency tree
Reading state information... Done
然后 sudo apt-get install ubuntu-desktop -s
~$ sudo apt-get install ubuntu-desktop -s
[sudo] password for mads:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:
The following packages have unmet dependencies:
ubuntu-desktop : Depends: unity-control-center but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
答案1
首先，您需要解决包裹被扣留的问题，请参见无法纠正问题，您持有破损的包裹然后继续下面的操作
安装 ubuntu-desktop 包。这将安装“正常” Unity 体验所需的一切。
sudo apt-get install ubuntu-desktop
如果这不起作用，你可以尝试重新安装 ubuntu-desktop 的所有依赖项
sudo apt-cache depends ubuntu-desktop | grep '[ |]Depends: [^<]' | cut -d: -f2 | tr -d ' ' | xargs sudo apt-get --reinstall install -y
命令借自：重新安装软件包及其安装的依赖项