我是这个论坛的新手，不是技术人员，但我很喜欢 Ubuntu，从 12.04 版开始就一直在用。
感谢所有在这里提供帮助的人。
自从下载 16.04 以来，Failed to download repository information当我使用软件更新程序时，我收到一条“ ”消息。我确实
update-manager -d
在终端中，返回结果为：
/usr/bin/update-manager:28: PyGIWarning: Gtk was imported without specifying a version first. Use gi.require_version('Gtk', '3.0') before import to ensure that the right version gets loaded.
from gi.repository import Gtk
/usr/lib/python3/dist-packages/UpdateManager/UnitySupport.py:29: PyGIWarning: Dbusmenu was imported without specifying a version first. Use gi.require_version('Dbusmenu', '0.4') before import to ensure that the right version gets loaded.
from gi.repository import Dbusmenu, Unity
/usr/lib/python3/dist-packages/UpdateManager/UnitySupport.py:29: PyGIWarning: Unity was imported without specifying a version first. Use gi.require_version('Unity', '7.0') before import to ensure that the right version gets loaded.
from gi.repository import Dbusmenu, Unity
谁能用简单的语言告诉我我需要做什么？
提前致谢。
编辑：输出sudo apt update
Get:1 security.ubuntu.com/ubuntu xenial-security InRelease [92.2 kB]
Hit:2 ppa.launchpad.net/dhor/myway/ubuntu xenial InRelease
Hit:3 gb.archive.ubuntu.com/ubuntu xenial InRelease
Get:4 gb.archive.ubuntu.com/ubuntu xenial-updates InRelease [92.2 kB]
Ign:5 ppa.launchpad.net/mscore-ubuntu/mscore-stable/ubuntu xenial InRelease
Hit:6 ppa.launchpad.net/noobslab/apps/ubuntu xenial InRelease
Hit:7 ppa.launchpad.net/rebuntu16/avidemux+unofficial/ubuntu xenial InRelease
Hit:8 gb.archive.ubuntu.com/ubuntu xenial-backports InRelease
Ign:9 ppa.launchpad.net/stebbins/handbrake-releases/ubuntu xenial InRelease
Hit:10 ppa.launchpad.net/webupd8team/tor-browser/ubuntu xenial InRelease
Err:11 ppa.launchpad.net/mscore-ubuntu/mscore-stable/ubuntu xenial Release 404 Not Found
Err:12 ppa.launchpad.net/stebbins/handbrake-releases/ubuntu xenial Release 404 Not Found Reading package lists... Done
E: The repository 'ppa.launchpad.net/mscore-ubuntu/mscore-stable/ubuntu xenial Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'ppa.launchpad.net/stebbins/handbrake-releases/ubuntu xenial Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
答案1
要更新您的系统，只需运行：
sudo apt-get update
sudo apt-get upgrade
sudo apt-get dist-upgrade