运行后apt update，apt upgrade我apt autoremove尝试运行do-release-upgrade。它失败并显示以下消息：
Could not calculate the upgrade
An unresolvable problem occurred while calculating the upgrade.
This was likely caused by:
* Unofficial software packages not provided by Ubuntu
Please use the tool 'ppa-purge' from the ppa-purge
package to remove software from a Launchpad PPA and
try the upgrade again.
If none of this applies, then please report this bug using the
command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal. If
you want to investigate this yourself the log files in
'/var/log/dist-upgrade' will contain details about the upgrade.
Specifically, look at 'main.log' and 'apt.log'.
我尝试运行ppa-purge并获取语法摘要。
我查看了这两个日志文件，它们并没有告诉我哪个 ppa 导致了这个问题。
apt.log超过 4000 行。以下是最后几行：
Starting pkgProblemResolver with broken count: 2
Starting 2 pkgProblemResolver with broken count: 2
Investigating (0) lightdm-settings:amd64 < 1.1.4-0ubuntu1 @ii mK Ib >
Broken lightdm-settings:amd64 Depends on python3-xapp:amd64 < 1.0.1-1 | 1.6.0-1 @ii ugR >
Considering python3-xapp:amd64 1 as a solution to lightdm-settings:amd64 1
Removing lightdm-settings:amd64 rather than change python3-xapp:amd64
MarkDelete lightdm-settings:amd64 < 1.1.4-0ubuntu1 @ii mK Ib > FU=0
Investigating (0) ubuntu-desktop:amd64 < 1.417.4 -> 1.440.1 @ii pumU NPb Ib >
Broken ubuntu-desktop:amd64 Depends on ubuntu-desktop-minimal:amd64 < none | 1.440.1 @un uH >
Considering ubuntu-desktop-minimal:amd64 1 as a solution to ubuntu-desktop:amd64 0
Ignore MarkKeep of ubuntu-desktop:amd64 < 1.417.4 -> 1.440.1 @ii pumU NPb Ib > as its mode (Install) is protected
Re-Instated ubuntu-desktop-minimal:amd64
Re-Instated ubuntu-desktop:amd64
Done
MarkInstall ubuntu-mate-desktop:amd64 < 1.225 -> 1.257 @ii ugU NPb IPb > FU=1
ignore old unsatisfied important dependency on ffmpegthumbnailer:amd64
new important dependency: gnome-mpv:amd64
Installing gnome-mpv as Recommends of ubuntu-mate-desktop
MarkInstall gnome-mpv:amd64 < none -> 0.16-1ubuntu1 @un uN Ib > FU=0
Installing libmpv1 as Depends of gnome-mpv
MarkInstall libmpv1:amd64 < none -> 0.29.1-1ubuntu1 @un uN IPb > FU=0
Installing youtube-dl as Recommends of libmpv1
MarkInstall youtube-dl:amd64 < none -> 2019.09.28-1 @un uN IPb > FU=0
Installing mpv as Recommends of youtube-dl
MarkInstall mpv:amd64 < none -> 0.29.1-1ubuntu1 @un uN > FU=0
Installing python3-pyxattr as Recommends of youtube-dl
MarkInstall python3-pyxattr:amd64 < none -> 0.6.1-1 @un uN > FU=0
previously satisfied important dependency on gufw:amd64
Installing gufw as Recommends of ubuntu-mate-desktop
MarkInstall gufw:amd64 < 18.04.0-0ubuntu1 -> 19.04.0-0ubuntu1 @ii ugU Ib > FU=0
Installing ufw as Depends of gufw
MarkInstall ufw:amd64 < 0.36-0ubuntu0.18.04.1 -> 0.36-1ubuntu3 @ii ugU > FU=0
previously satisfied important dependency on lightdm-settings:amd64
Installing lightdm-settings as Recommends of ubuntu-mate-desktop
MarkKeep lightdm-settings:amd64 < 1.1.4-0ubuntu1 @ii gR > FU=0
previously satisfied important dependency on redshift-gtk:amd64
Installing redshift-gtk as Recommends of ubuntu-mate-desktop
MarkInstall redshift-gtk:amd64 < 1.11-1ubuntu1 -> 1.12-2 @ii ugU > FU=0
previously satisfied important dependency on rhythmbox-plugin-alternative-toolbar:amd64
Installing rhythmbox-plugin-alternative-toolbar as Recommends of ubuntu-mate-desktop
MarkInstall rhythmbox-plugin-alternative-toolbar:amd64 < 0.18.0-1 -> 0.18.4-1 @ii ugU > FU=0
Starting pkgProblemResolver with broken count: 1
Starting 2 pkgProblemResolver with broken count: 1
Investigating (0) lightdm-settings:amd64 < 1.1.4-0ubuntu1 @ii mK Ib >
Broken lightdm-settings:amd64 Depends on python3-xapp:amd64 < 1.0.1-1 | 1.6.0-1 @ii ugR >
Considering python3-xapp:amd64 1 as a solution to lightdm-settings:amd64 3
Added python3-xapp:amd64 to the remove list
Fixing lightdm-settings:amd64 via keep of python3-xapp:amd64
MarkKeep python3-xapp:amd64 < 1.0.1-1 | 1.6.0-1 @ii ugR > FU=0
Done
Log time: 2020-04-29 19:49:21.097217
main.log由于文件中的链接太多，网站软件不允许我发帖。
答案1
版本间升级do-release-upgradeUbuntu 必须遵循以下规则：
- 升级只应针对受支持的版本进行（而不是针对已过期的版本）。
- 可以升级到下一个版本，例如从 19.10 升级到 20.04
- 当第一个版本发布（七月下旬或八月初）时，可以从一个 LTS 版本升级到下一个 LTS 版本，例如从 18.04.x LTS 升级到 20.04.1 LTS。
在您的情况下，升级应逐步进行 18.04 --> 18.10 --> 19.04 --> 19.10，但 18.10 和 19.04 已超过使用寿命，因此不起作用。
但如果您等到 7 月底或 8 月初，您将能够升级到 20.04.1 LTS。
请参阅此链接（并向下滚动到“如果您想要顺利骑行”）了解更多详情：
答案2
一位朋友提出了一个解决问题的建议。在图形“软件和更新”应用中，在“其他”下，取消选中每一个ppa 并再次运行。这对我来说很有效。我确实看到我必须在 /etc/apt 中的配置文件中将“bionic”更改为“eoan”，然后才能重新启用我的 ppa 文件。