首先，我尝试了很多方法，但都没有用。我使用的是戴尔 Inspiron 5570 和双启动的 ubuntu 18.10（从 18.04 升级）和 Windows。以下是一些输出：
systemd-analyze
Startup finished in 9.741s (firmware) + 8.671s (loader) + 5.543s (kernel) + 1min 1.259s (userspace) = 1min 25.215s
graphical.target reached after 1min 1.239s in userspace
systemd-analyze critical-chain
The time after the unit is active or started is printed after the "@" character.
The time the unit takes to start is printed after the "+" character.
graphical.target @1min 1.239s
└─multi-user.target @1min 1.239s
└─teamviewerd.service @59.453s +1.785s
└─network-online.target @59.451s
└─NetworkManager-wait-online.service @45.485s +13.964s
└─NetworkManager.service @38.320s +7.163s
└─dbus.service @38.316s
└─basic.target @37.136s
└─sockets.target @37.136s
└─snapd.socket @37.121s +14ms
└─sysinit.target @36.927s
└─haveged.service @36.926s
└─apparmor.service @32.777s +4.148s
└─local-fs.target @32.732s
└─boot-efi.mount @32.616s +116ms
└─systemd-fsck@dev-disk-by\x2duuid-9EE8\x2d695F.serv
└─dev-disk-by\x2duuid-9EE8\x2d695F.device @30.536s
systemd-analyze blame
24.686s dev-sda8.device
20.600s systemd-journal-flush.service
15.304s udisks2.service
14.904s apport-autoreport.service
14.380s networkd-dispatcher.service
13.964s NetworkManager-wait-online.service
13.053s ModemManager.service
12.915s snapd.service
12.856s accounts-daemon.service
10.455s dev-loop9.device
10.203s dev-loop18.device
10.044s dev-loop19.device
9.971s dev-loop20.device
9.961s dev-loop13.device
9.931s dev-loop11.device
9.443s dev-loop17.device
9.221s dev-loop10.device
9.198s dev-loop12.device
9.010s dev-loop15.device
8.940s dev-loop16.device
8.668s avahi-daemon.service
8.594s dev-loop8.device
8.491s networking.service
8.425s dev-loop14.device
8.236s systemd-logind.service
8.236s thermald.service
8.235s bluetooth.service
8.232s grub-common.service
8.226s gpu-manager.service
8.192s alsa-restore.service
8.189s apport.service
8.072s dev-loop7.device
7.677s dev-loop2.device
7.414s dev-loop5.device
7.163s NetworkManager.service
7.162s wpa_supplicant.service
7.101s rsyslog.service
7.101s switcheroo-control.service
6.810s plymouth-quit-wait.service
6.290s dev-loop6.device
6.178s colord.service
6.115s dev-loop4.device
5.934s dev-loop3.device
5.876s dev-loop0.device
5.867s dev-loop1.device
4.568s systemd-udevd.service
4.148s apparmor.service
3.488s gdm.service
2.794s systemd-rfkill.service
2.264s keyboard-setup.service
2.047s systemd-fsck@dev-disk-by\x2duuid-9EE8\x2d695F.service
2.001s systemd-resolved.service
1.870s snap-gnome\x2d3\x2d26\x2d1604-74.mount
1.854s openvpn.service
1.788s snap-gnome\x2dcalculator-238.mount
1.785s teamviewerd.service
1.575s systemd-modules-load.service
1.562s dns-clean.service
1.509s systemd-sysusers.service
1.484s fwupd.service
1.468s polkit.service
1.438s snap-gnome\x2dsystem\x2dmonitor-54.mount
1.429s snap-gtk\x2dcommon\x2dthemes-808.mount
1.428s systemd-tmpfiles-setup.service
1.428s snap-gnome\x2dsystem\x2dmonitor-51.mount
1.388s snap-core-6034.mount
1.377s snap-gtk\x2dcommon\x2dthemes-701.mount
1.346s snap-gnome\x2dcalculator-222.mount
1.318s grub-initrd-fallback.service
1.317s snap-gtk\x2dcommon\x2dthemes-818.mount
1.311s snap-core-6259.mount
1.221s kerneloops.service
1.196s pppd-dns.service
1.195s sysstat.service
1.036s systemd-sysctl.service
1.013s snap-gnome\x2d3\x2d26\x2d1604-70.mount
993ms console-setup.service
992ms systemd-tmpfiles-setup-dev.service
990ms packagekit.service
886ms snap-core-6130.mount
862ms swapfile.swap
712ms snap-gnome\x2dcharacters-124.mount
681ms systemd-backlight@backlight:intel_backlight.service
679ms systemd-backlight@leds:dell::kbd_backlight.service
652ms snap-gnome\x2dlogs-45.mount
639ms snap-gnome\x2dcharacters-117.mount
624ms systemd-timesyncd.service
598ms systemd-journald.service
592ms snap-gnome\x2dlogs-40.mount
584ms snap-gnome\x2d3\x2d26\x2d1604-59.mount
560ms systemd-random-seed.service
552ms snap-gnome\x2dcalculator-260.mount
543ms upower.service
536ms snap-gnome\x2dcharacters-139.mount
522ms snap-gnome\x2dlogs-43.mount
481ms systemd-udev-trigger.service
455ms dev-mqueue.mount
436ms dev-hugepages.mount
436ms kmod-static-nodes.service
435ms systemd-remount-fs.service
435ms sys-kernel-debug.mount
434ms ufw.service
387ms systemd-user-sessions.service
372ms plymouth-read-write.service
371ms plymouth-start.service
286ms snapd.seeded.service
219ms snap-gnome\x2dsystem\x2dmonitor-57.mount
200ms setvtrgb.service
145ms bolt.service
131ms systemd-update-utmp.service
116ms boot-efi.mount
88ms [email protected]
80ms ifupdown-pre.service
24ms rtkit-daemon.service
15ms systemd-update-utmp-runlevel.service
14ms snapd.socket
1ms sys-fs-fuse-connections.mount
1ms sys-kernel-config.mount