我最近从 21.04 升级到了 21.10，升级过程很顺利，没有出现任何错误，但现在 Ubuntu 会随机关机。不过也没有崩溃。关机提示随机出现，有立即关机或取消的选项，60 秒倒计时就像我告诉它关机一样，但即使我立即点击取消，计算机也会关机。
（这是在 System 76 Lemur 上发生的，在升级之前没有出现此问题。）
抱歉，我对细节了解得不太清楚，我不确定什么是相关的，因为我不知道是什么原因导致它弹出关闭对话框，然后不管怎样就关闭？
根据要求编辑以添加 /var/log/syslog 中的相关部分。抱歉，花了这么长时间才添加。今天早些时候，它在 20 分钟内两次自动关闭，但当然，当我等待找到确切的时间来检查日志时，因为我不记得确切的上次时间，它花了 2 个多小时才再次自动关闭。无论如何，这是它最后一次关闭时的系统日志，这是整整一分钟，所以我希望导致问题的原因就在那里。我查看了它是什么，但这超出了我的能力范围。
Nov 7 22:02:10 mildred systemd[1]: fwupd.service: Deactivated successfully.
Nov 7 22:02:51 mildred NetworkManager[3396]: <info> [1636340571.9197] manager: NetworkManager state is now CONNECTED_SIT
Nov 7 22:02:51 mildred dbus-daemon[3395]: [system] Activating via systemd: service name='org.freedesktop.nm_dispatcher' unit='dbus-org.freedesktop.nm-dispatcher.service' requested by ':1.7' (uid=0 pid=3396 comm="/usr/sbin/NetworkManager --no-daemon " label="unconfined")
Nov 7 22:02:51 mildred telegram-deskto[5110]: GDBus.Error:org.freedesktop.portal.Error.NotAllowed: This call is not available inside the sandbox
Nov 7 22:02:51 mildred systemd[1]: Starting Network Manager Script Dispatcher Service...
Nov 7 22:02:51 mildred systemd[1]: Starting Laptop Mode Tools - Battery Polling Service...
Nov 7 22:02:51 mildred systemd[1]: lmt-poll.service: Deactivated successfully.
Nov 7 22:02:51 mildred sh[10132]: laptop-mode: Battery polling disabled
Nov 7 22:02:51 mildred systemd[1]: Finished Laptop Mode Tools - Battery Polling Service.
Nov 7 22:02:51 mildred dbus-daemon[3395]: [system] Successfully activated service 'org.freedesktop.nm_dispatcher'
Nov 7 22:02:51 mildred systemd[1]: Started Network Manager Script Dispatcher Service.
Nov 7 22:02:51 mildred whoopsie[4648]: [22:02:51] Cannot reach: https://daisy.ubuntu.com
Nov 7 22:02:51 mildred whoopsie[4648]: [22:02:51] offline
Nov 7 22:02:51 mildred NetworkManager[3396]: <info> [1636340571.9972] manager: NetworkManager state is now CONNECTED_GLOBAL
Nov 7 22:02:52 mildred telegram-deskto[5110]: GDBus.Error:org.freedesktop.portal.Error.NotAllowed: This call is not available inside the sandbox
Nov 7 22:02:52 mildred whoopsie[4648]: [22:02:52] Cannot reach: https://daisy.ubuntu.com
Nov 7 22:02:52 mildred whoopsie[4648]: [22:02:52] The default IPv4 route is: /org/freedesktop/NetworkManager/ActiveConnection/1
Nov 7 22:02:52 mildred whoopsie[4648]: [22:02:52] Not a paid data plan: /org/freedesktop/NetworkManager/ActiveConnection/1
Nov 7 22:02:52 mildred whoopsie[4648]: [22:02:52] Found usable
connection: /org/freedesktop/NetworkManager/ActiveConnection/1
Nov 7 22:02:52 mildred telegram-deskto[5110]: GDBus.Error:org.freedesktop.portal.Error.NotAllowed: This call is not available inside the sandbox
Nov 7 22:02:52 mildred whoopsie[4648]: [22:02:52] online