Introduction

When you reboot after installing Ubuntu on a big disk (>100GB), you may get a boot error (eg "GRUB rescue>", or "Error: unknown file system", or "error: Out of disk").

Here is how to solve this problem:

Procedure

Step 1 - try the Recommended Repair of Boot-Repair

• Boot your computer on a Ubuntu-Secure-Remix liveCD or liveUSB

• choose "Try Ubuntu"

• launch Boot-Repair from the Dash (click the Ubuntu logo in the top-left corner of the screen, then type boot and click on the Boot-Repair icon that will appear).

• click the "Recommended repair" button

• reboot the computer

• if you still can't access Ubuntu, go to Step 2 below.

Step 2 - try the out-of-disk option

• Boot your computer on a Ubuntu-Secure-Remix liveCD or liveUSB

• choose "Try Ubuntu"

• launch Boot-Repair from the Dash (click the Ubuntu logo in the top-left corner of the screen, then type boot and click on the Boot-Repair icon that will appear).

• click "Advanced option"
• go to the "GRUB options" tab

• tick the "out-of-disk" option

• click "Apply"
• reboot the computer

• if you still can't access Ubuntu, go to Step 3 below.

Step 3 - Create a separate boot partition

• follow the following procedure: HOWTO create a separate /boot partition.

• reboot the computer. You should now get access to Ubuntu.

Remarks

- if you need help, please create your new own thread here (don't forget to indicate the URL you noted on your paper at Step6, this will give valuable information to understand your problem)

External Links

- Discussion thread on ubuntuforums for any question/comment about this tutorial. (this is not a thread for support)