我已经在虚拟机上安装了 Ubuntu，以便我将一些在 Windows 上使用的应用程序移到虚拟机上。
但似乎如果我离开虚拟机一段时间，它就会关闭。当我使用它时，虚拟机会关闭。这不是休眠或待机，因为当我启动虚拟机时，它会运行完整的启动，并且不再打开任何应用程序。
可能是什么原因导致的以及如何禁用它以使其保持开启状态？
更新：这是日志，我没有找到任何可以解释关机原因的内容。
systemd[1]: Unmounted Mount unit for snap-store, revisi>
systemd[1]: snap-snapd-8542.mount: Succeeded.
systemd[1]: Unmounted Mount unit for snapd, revision 85>
systemd[1]: Stopped target Local File Systems (Pre).
systemd[1]: Reached target Unmount All Filesystems.
systemd[1]: systemd-tmpfiles-setup-dev.service: Succeed>
systemd[1]: Stopped Create Static Device Nodes in /dev.
systemd[1]: systemd-sysusers.service: Succeeded.
systemd[1]: Stopped Create System Users.
systemd[1]: systemd-remount-fs.service: Succeeded.
systemd[1]: Stopped Remount Root and Kernel File System>
systemd[1]: Reached target Shutdown.
systemd[1]: Reached target Final Step.
systemd[1]: systemd-poweroff.service: Succeeded.
systemd[1]: Finished Power-Off.
systemd[1]: Reached target Power-Off.
systemd[1]: Shutting down.
systemd-shutdown[1]: Syncing filesystems and block devi>
systemd-shutdown[1]: Sending SIGTERM to remaining proce>
VGAuthService[613]: Processing SIGTERM; service exiting
VGAuthService[613]: ServiceEndMainLoop: about to stop m>
VGAuthService[613]: END SERVICE
systemd-journald[366]: Journal stopped
lines 981-1003/1003 (END)
systemd[1]: Unmounted Mount unit for snap-store, revision 467.
systemd[1]: snap-snapd-8542.mount: Succeeded.
systemd[1]: Unmounted Mount unit for snapd, revision 8542.
systemd[1]: Stopped target Local File Systems (Pre).
systemd[1]: Reached target Unmount All Filesystems.
systemd[1]: systemd-tmpfiles-setup-dev.service: Succeeded.
systemd[1]: Stopped Create Static Device Nodes in /dev.
systemd[1]: systemd-sysusers.service: Succeeded.
systemd[1]: Stopped Create System Users.
systemd[1]: systemd-remount-fs.service: Succeeded.
systemd[1]: Stopped Remount Root and Kernel File Systems.
systemd[1]: Reached target Shutdown.
systemd[1]: Reached target Final Step.
systemd[1]: systemd-poweroff.service: Succeeded.
systemd[1]: Finished Power-Off.
systemd[1]: Reached target Power-Off.
systemd[1]: Shutting down.
systemd-shutdown[1]: Syncing filesystems and block devices.
systemd-shutdown[1]: Sending SIGTERM to remaining processes...
VGAuthService[613]: Processing SIGTERM; service exiting
VGAuthService[613]: ServiceEndMainLoop: about to stop main loop
VGAuthService[613]: END SERVICE
systemd-journald[366]: Journal stopped
~
~
~
~
~
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lines 981-1003/1003 (END)
systemd[1]: Unmounted Mount unit for snap-store, revision 467.
systemd[1]: snap-snapd-8542.mount: Succeeded.
systemd[1]: Unmounted Mount unit for snapd, revision 8542.
systemd[1]: Stopped target Local File Systems (Pre).
systemd[1]: Reached target Unmount All Filesystems.
systemd[1]: systemd-tmpfiles-setup-dev.service: Succeeded.
systemd[1]: Stopped Create Static Device Nodes in /dev.
systemd[1]: systemd-sysusers.service: Succeeded.
systemd[1]: Stopped Create System Users.
systemd[1]: systemd-remount-fs.service: Succeeded.
systemd[1]: Stopped Remount Root and Kernel File Systems.
systemd[1]: Reached target Shutdown.
systemd[1]: Reached target Final Step.
systemd[1]: systemd-poweroff.service: Succeeded.
systemd[1]: Finished Power-Off.
systemd[1]: Reached target Power-Off.
systemd[1]: Shutting down.
systemd-shutdown[1]: Syncing filesystems and block devices.
systemd-shutdown[1]: Sending SIGTERM to remaining processes...
VGAuthService[613]: Processing SIGTERM; service exiting
VGAuthService[613]: ServiceEndMainLoop: about to stop main loop
VGAuthService[613]: END SERVICE
systemd-journald[366]: Journal stopped