我的 Ubuntu 安装需要一分多钟才能启动……这个问题我已经遇到好久了。我已经关闭了安全启动（我总是收到“PKCS#7 未使用受信任密钥签名”错误）。这是 的输出systemd-analyze blame：
16.818s systemd-journal-flush.service
16.519s systemd-udevd.service
16.064s snapd.service
13.623s dev-loop21.device
13.546s dev-loop10.device
13.442s dev-loop22.device
13.252s dev-loop13.device
13.067s dev-loop14.device
13.060s dev-loop23.device
12.996s dev-loop3.device
12.986s dev-loop6.device
12.960s dev-loop18.device
12.954s dev-loop16.device
12.951s dev-loop15.device
12.949s dev-loop12.device
12.882s dev-loop24.device
12.862s dev-loop27.device
12.822s dev-loop17.device
12.413s dev-loop25.device
12.337s ModemManager.service
12.336s dev-loop26.device
12.261s dev-loop9.device
12.116s dev-loop7.device
12.103s networkd-dispatcher.service
12.077s NetworkManager-wait-online.service
11.930s dev-loop20.device
11.809s gpu-manager.service
11.692s dev-loop19.device
11.512s dev-loop11.device
11.393s dev-loop5.device
11.140s dev-loop2.device
11.137s dev-loop0.device
10.934s dev-loop8.device
10.700s dev-loop4.device
10.029s dev-loop1.device
9.770s NetworkManager.service
7.673s grub-common.service
6.692s bluetooth.service
6.331s udisks2.service
6.253s snap-gtk\x2dcommon\x2dthemes-1313.mount
6.207s accounts-daemon.service
5.738s wpa_supplicant.service
5.508s snap-gnome\x2d3\x2d28\x2d1804-63.mount
5.212s systemd-logind.service
5.060s pppd-dns.service
4.827s snap-core18-1049.mount
4.796s snap-pycharm\x2dcommunity-132.mount
4.706s rsyslog.service
4.699s speech-dispatcher.service
4.686s apport.service
4.414s snap-canonical\x2dlivepatch-81.mount
4.347s snap-gnome\x2d3\x2d28\x2d1804-67.mount
3.896s snap-gnome\x2d3\x2d26\x2d1604-88.mount
3.840s tlp.service
3.790s apparmor.service
3.510s snap-gnome\x2dcalculator-352.mount
3.238s snap-google\x2dplay\x2dmusic\x2ddesktop\x2dplayer-70.mount
2.957s snap-gnome\x2dcalculator-260.mount
2.800s networking.service
2.748s snap-core18-1066.mount
2.676s systemd-tmpfiles-setup-dev.service
2.558s thermald.service
2.486s snap-discord-93.mount
2.287s snap-gtk\x2dcommon\x2dthemes-1198.mount
2.242s gdm.service
2.156s apport-autoreport.service
2.125s snap-core-7270.mount
2.119s systemd-backlight@backlight:intel_backlight.service
2.028s setvtrgb.service
2.009s systemd-modules-load.service
1.990s [email protected]
1.972s snap-canonical\x2dlivepatch-77.mount
1.903s keyboard-setup.service
1.853s snap-gnome\x2dlogs-45.mount
1.835s snap-netbeans-6.mount
1.735s systemd-backlight@leds:dell::kbd_backlight.service
1.731s snap-gnome\x2dcharacters-296.mount
1.649s snap-gnome\x2d3\x2d26\x2d1604-90.mount
1.438s systemd-tmpfiles-setup.service
1.434s systemd-random-seed.service
1.314s snap-core-7169.mount
1.103s avahi-daemon.service
1.016s snap-gnome\x2dsystem\x2dmonitor-95.mount
906ms plymouth-read-write.service
898ms snap-netbeans-10.mount
881ms swapfile.swap
864ms snap-gnome\x2dcharacters-292.mount
858ms packagekit.service
843ms snap-pycharm\x2dcommunity-143.mount
759ms snap-gnome\x2dcalculator-406.mount
655ms snap-gnome\x2dlogs-61.mount
587ms snap-gnome\x2dsystem\x2dmonitor-100.mount
586ms sys-kernel-debug.mount
585ms ufw.service
579ms systemd-journald.service
406ms polkit.service
398ms systemd-resolved.service
370ms systemd-fsck@dev-disk-by\x2duuid-6030\x2d6C29.service
363ms systemd-timesyncd.service
265ms snapd.socket
218ms snap-gnome\x2dlogs-57.mount
214ms systemd-hostnamed.service
180ms systemd-remount-fs.service
174ms systemd-sysctl.service
173ms kmod-static-nodes.service
150ms systemd-update-utmp.service
146ms upower.service
115ms bolt.service
104ms [email protected]
87ms nvidia-persistenced.service
73ms dev-hugepages.mount
70ms dev-mqueue.mount
69ms colord.service
51ms systemd-udev-trigger.service
39ms snapd.seeded.service
37ms rtkit-daemon.service
10ms alsa-restore.service
6ms kerneloops.service
5ms boot-efi.mount
4ms dns-clean.service
3ms systemd-update-utmp-runlevel.service
3ms ureadahead-stop.service
3ms sys-fs-fuse-connections.mount
3ms sys-kernel-config.mount
2ms systemd-user-sessions.service
2ms console-setup.service
1ms plymouth-quit-wait.service
和这是 的输出dmesg。如您所见，存在一些错误，包括多个 PKCS 错误。
我还被要求提供的输出systemd-analyze critical chain，因此这里是：https://pastebin.com/VBtjjThw。