Dell PC开机无法识别OS求助：Ubuntu 17.10更新后异常

Hey there, let's work through this Ubuntu boot issue you're having—sounds like a post-update GRUB glitch, which is pretty common when large updates get interrupted mid-restart. First, let's recap your scenario to make sure I'm on the same page:

两天前正常启动Dell PC，出现Dell logo后进入陌生的硬件检测白屏，检测完成显示所有硬件正常，但系统提示无OS需加载操作系统；此前一天使用Ubuntu 17.10正常办公，设备正在大量更新且多次提示重启。

1. Double-Check BIOS Boot Priority #

Sometimes after updates, the BIOS can reset or misorder boot devices. Let's rule this out first:

• Restart your Dell PC, and as soon as the Dell logo pops up, press the BIOS entry key (usually F2, F12, or Del—watch the tiny on-screen text for the exact key)
• Navigate to the Boot tab in the BIOS menu
• Make sure the hard drive where Ubuntu is installed (it'll show the drive brand/model, like "Samsung SSD 860 EVO") is set as the top boot option
• Save your changes (hit F10 usually) and restart—see if the system boots normally now

2. Repair the GRUB Bootloader (Most Likely Fix) #

Large Ubuntu updates often touch the GRUB bootloader, and an interrupted restart can corrupt it. Here's how to fix it using a live USB:

• If you don't already have one, create a Ubuntu 17.10 installation USB on another PC (use the official ISO file)
• Plug the USB into your Dell, restart, and press F12 to open the boot menu—select the USB drive
• Choose "Try Ubuntu without installing" to load the live environment
• Open a terminal with Ctrl+Alt+T
• First, find your Ubuntu root partition: run sudo fdisk -l and look for the entry labeled Linux filesystem (it might be /dev/sda1, /dev/nvme0n1p2 for NVMe drives)
• Mount that partition to the live system: sudo mount /dev/sda1 /mnt (replace /dev/sda1 with your actual partition path)
• Bind the critical system directories so we can "jump into" your installed OS:

  sudo mount --bind /dev /mnt/dev
  sudo mount --bind /proc /mnt/proc
  sudo mount --bind /sys /mnt/sys
  

• Chroot into your installed system: sudo chroot /mnt
• Reinstall GRUB to your main hard drive: sudo grub-install /dev/sda (note: this is the drive, not the partition—so /dev/sda, not /dev/sda1)
• Update the GRUB config to recognize your Ubuntu installation: sudo update-grub
• Exit chroot and clean up the mounts:

  exit
  sudo umount /mnt/sys
  sudo umount /mnt/proc
  sudo umount /mnt/dev
  sudo umount /mnt
  

• Restart your PC, remove the USB, and your Ubuntu should boot back up

3. Check for Disk Partition Corruption #

If GRUB repair doesn't work, the update might have messed up your filesystem:

• From the live Ubuntu environment, open the Disks app (search for it in the launcher)
• Select your main hard drive and check if the Ubuntu partition is still listed and marked as "Mountable"
• If it looks corrupted, run a filesystem check in the terminal:

  sudo fsck /dev/sda1
  

  Follow the on-screen prompts to fix any errors—this might take a few minutes depending on your drive size

4. Last Resort: Reinstall Ubuntu (Keep Personal Files) #

If all else fails, you can reinstall Ubuntu without wiping your documents, pictures, etc.:

• Boot from the Ubuntu 17.10 USB and select "Install Ubuntu"
• When you get to the "Installation type" screen, choose "Something else"
• Select your existing Ubuntu root partition, set its mount point to /, and make sure the "Format" box is unchecked
• Continue with the installation—this will overwrite the system files but leave your personal data intact

内容的提问来源于stack exchange，提问作者Nermeen Hussein