Ubuntu 22.04崩溃后无法启动，双系统环境下修复及数据恢复求助

Hey there, sorry to hear you're stuck with this frustrating boot issue after Ubuntu crashed and your Windows update—let's work through this step by step to either get Ubuntu back up or at least rescue your important files first.

先确认磁盘状态（确保数据安全） #

Since your Ubuntu is on a separate SSD, first let's check if the disk is still recognized in Windows:

• Open Disk Management (right-click the Start menu and select it). Look for unassigned/non-Windows partitions (no drive letters, usually labeled as "Linux Filesystem" or "EFI System"). If you can see them, your SSD is physically fine, and your data is almost certainly safe. That's a huge relief.

修复GRUB引导（优先恢复Ubuntu启动） #

Your earlier bcdedit commands didn't work—this is likely because either the EFI path was incorrect, or Ubuntu's GRUB itself got corrupted. The most reliable fix is using an Ubuntu installation drive:

1. Create an Ubuntu 22.04 installation USB (use tools like Rufus, make sure to select the correct ISO and use "DD mode" or "ISO Image mode").
2. Plug in the USB, restart your PC, and boot from it (press F12/F2/Del to enter BIOS boot menu—key varies by brand).
3. When you reach the Ubuntu setup screen, select "Try Ubuntu" (don't click "Install Ubuntu") to enter the live environment.
4. Open the terminal (press Ctrl+Alt+T), then identify your Ubuntu partitions:
   • Run sudo fdisk -l to list all disks/partitions. Look for:
     • The main Ubuntu system partition (labeled Linux filesystem, usually something like /dev/nvme0n1p2 or /dev/sda2).
     • The EFI system partition (labeled EFI System, usually /dev/nvme0n1p1 or /dev/sda1).
5. Mount your Ubuntu root partition:
   • Assuming your root partition is /dev/sda2, run:

     sudo mount /dev/sda2 /mnt
     

6. Mount the EFI partition:
   • If your EFI partition is /dev/sda1, run:

     sudo mount /dev/sda1 /mnt/boot/efi
     

7. Repair GRUB:
   • Install GRUB to your Ubuntu SSD (note: use the disk name like /dev/sda, not a partition):

     sudo grub-install --boot-directory=/mnt/boot --efi-directory=/mnt/boot/efi /dev/sda
     

   • Update GRUB to detect both Ubuntu and Windows:

     sudo update-grub
     

8. Reboot your PC, remove the USB, and check if the GRUB boot menu appears—you should be able to select Ubuntu now.

如果GRUB修复失败，先抢救重要数据 #

If the above steps don't bring Ubuntu back, your system might have some corrupted files—but don't panic, your data is still retrievable:

1. Stay in the Ubuntu live environment (the "Try Ubuntu" mode). Open the file manager, and you'll see your Ubuntu disk listed on the left sidebar. Click it to mount it (you might need to enter your sudo password).
2. Once mounted, you can browse through your files just like normal. Copy all important data (like documents, photos, or projects from /home/your-username/) to an external USB drive or even your Windows NTFS partition (Ubuntu can read/write NTFS partitions directly).
3. Alternatively, if you prefer staying in Windows, install a tool that supports ext4 partitions (like Paragon ExtFS for Windows). After installation, you'll be able to access your Ubuntu files directly from Windows Explorer and copy them over.

关于系统损坏的可能性 #

The earlier crashes (taskbar icons turning gray, unresponsive system) followed by the missing boot entry are most likely due to GRUB corruption—Windows updates sometimes overwrite EFI boot entries, which can break dual-boot setups. If you can't repair GRUB, it's possible some system files got damaged during the crash, but that's rare if the disk is healthy. After recovering your data, you can either try a fresh Ubuntu install (formatting the old Ubuntu partition) or attempt a system repair from the live environment.

备注：内容来源于stack exchange，提问作者Luketis