关机过程最后显示的是 Failed to umount /var。

在两台不同机器上均出现这同一个问题，Ryzen1700+b350和ryzen5600+b450，都为多块硬盘，其中一台为新装的系统。

journalctl -x显示的日志为：

░░ The unit UNIT completed and consumed the indicated resources.
3月 06 23:10:52 fresh-PC systemd[1752]: dde-file-manager.service: State 'final-sigterm' timed out. Killing.
3月 06 23:10:52 fresh-PC systemd[1752]: dde-file-manager.service: Killing process 33998 (dde-file-manage) with signal SIGKILL.
3月 06 23:10:52 fresh-PC systemd[1752]: dde-file-manager.service: Failed to kill control group /user.slice/user-1000.slice/user@1000.service/app.slice/dde-file-manager.service, ignoring: Invalid argument
3月 06 23:10:52 fresh-PC systemd[1752]: dde-file-manager.service: Failed with result 'timeout'.
░░ Subject: Unit failed
░░ Defined-By: systemd
░░ Support: https://www.debian.org/support

请问有什么办法解决么？
░░
░░ The unit UNIT has entered the 'failed' state with result 'timeout'.