sudo do-release-upgrade今天早上运行将我的系统从 Ubtunu 17.10 升级到 18.04 LTS后，我在升级过程中遇到了错误。跟踪太长而无法完整发布，但这是（对我而言）看起来像问题的部分：
Rebuilding /usr/share/applications/bamf-2.index...
Errors were encountered while processing:
shim-signed
grub-efi-amd64-signed
Exception during pm.DoInstall(): E:Sub-process /usr/bin/dpkg returned an error code (1)
Could not install the upgrades
The upgrade has aborted. Your system could be in an unusable state. A
recovery will run now (dpkg --configure -a).
Setting up shim-signed (1.34.9+13-0ubuntu2) ...
Installing for x86_64-efi platform.
Could not add entry to BootOrder: Interrupted system call
grub-install: error: efibootmgr failed to register the boot entry: No such device or address.
dpkg: error processing package shim-signed (--configure):
installed shim-signed package post-installation script subprocess returned error exit status 1
Setting up grub-efi-amd64-signed (1.93+2.02-2ubuntu8) ...
Installing for x86_64-efi platform.
Could not add entry to BootOrder: Interrupted system call
grub-install: error: efibootmgr failed to register the boot entry: No such device or address.
dpkg: error processing package grub-efi-amd64-signed (--configure):
installed grub-efi-amd64-signed package post-installation script subprocess returned error exit status 1
Errors were encountered while processing:
shim-signed
grub-efi-amd64-signed
Upgrade complete
The upgrade has completed but there were errors during the upgrade process.
我浏览了论坛的解决方案，可以先发制人地确认其中的条目没有/etc/fstab被注释掉。cat /etc/fstab输出以下内容：
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/sda9 during installation
UUID=a2f91309-dc7e-4456-b3ef-89900b145365 / ext4 errors=remount-ro 0 1
# /boot/efi was on /dev/sda2 during installation
UUID=90EA-4FB8 /boot/efi vfat umask=0077 0 1
# swap was on /dev/sda6 during installation
UUID=2f80d8f4-5609-45e1-854d-578ab25836c3 none swap sw 0 0
该系统是双启动的 Windows 10。通过lsb_release -a我可以确认我的 Ubuntu 分区确实更新到 18.04 LTS，但这些错误让我感到不安，我不希望它们长期造成问题。谢谢你。