This document belongs to Manual Full System Encryption (with Extras).
If you hit a problem that this troubleshooting guide doesn't help, you can ask for support. In all cases, it might be helpful to point to these instructions so that people know what you are trying to do.
The Ubuntu Forums is a friendly and welcoming place, with a section just for beginners, or you might prefer the section for Installation and Upgrades.
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2. Computer fails to boot after upgrade or new installation
On rare occasions, you might find that the computer fails to boot. This can happen if Windows makes a major (not necessarily large) update, or if Grub becomes corrupted in some other way.
- Boot into a Live CD.
- Open a terminal.
To unlock your partition, enter the following command. Replace /dev/SYSTEM_PARTITION with your system partition, e.g. /dev/sda5 or /dev/nvme01n1p5. You will be prompted for your system passphrase.
sudo cryptsetup open --type=luks /dev/SYSTEM_PARTITION system
Mount your system partition. Replace /dev/EFI_PARTITION with your EFI System Partition (ESP), e.g. /dev/sda2 or /dev/nvme01n1p2.
sudo mkdir /mnt/root sudo mount /dev/mapper/system-root /mnt/root sudo mount /dev/mapper/system-boot /mnt/root/boot sudo mount /dev/EFI_PARTITION /mnt/root/boot/efi
Enter something called chroot (don't worry about what it means).
sudo mount --bind /dev /mnt/root/dev sudo mount --bind /run /mnt/root/run sudo chroot /mnt/root mount --types=proc proc /proc mount --types=sysfs sys /sys
- Fix Grub. This might take a couple of minutes to run.
- Enter the following command.
- Close all open windows, and reboot your computer.
2.1. Still failing to fix the boot?
Please see this helpful post and this helpful script.