计算升级时出现无法解决的问题：
The package 'unity' is marked for removal but it is in the removal blacklist.
This can be caused by:
* Upgrading to a pre-release version of Ubuntu
* Running the current pre-release version of Ubuntu
* Unofficial software packages not provided by Ubuntu
If none of this applies, then please report this bug using the
command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal.
我该怎么办？我需要将 untiy 从黑名单中删除吗？该怎么做？
答案1
选项1：
update manager -d
选项 2：
Step 1: Install Gnome
Step 2: Log in Through Gnome
Step 3: Uninstall unity using Synaptic
Step 4: Try upgrade