Ubuntu won’t boot without USB stick

As some of you may remember, a few weeka ago I posted an article about installing Ubuntu from USB (If you can’t remember, check it out!), which explained how to get an ISO running on a machine without an optical device. Well it turns out that wasn’t entirely the end of the situation for some…

Ubuntu wont boot – black screen?

It seems that there is a bug in Precise Pangolin which means that if you install your OS from a USB flash disk or hard drive, the important grub screen sometimes gets installed back onto this device.

If this is the case, Ubuntu won’t boot and a black screen is all you’ll see when you boot without the USB disk in the machine. You may have a flashing white character in the top left too. Both of these mean the computer is waiting to receive instructions on what operating system it should load. Sadly, it should get this information automatically via the grub screen.

Fixing Ubuntu’s boot problem

To solve this problem, first off open up terminal and run the following:

sudo fdisk -l

(Thats a lowecase L, not a 1)

This will show you the partition tables on your machine.

The screen shot below shows what my partition table looked like:

The important thing to notice is what your hard drive is called. Using the information I can see my 250Gb drive is the disk labelled /dev/sda, which is what I’d expect. SD* are mass storage devices and they’re labelled in order, so SDA is the primary one it found, SDB is the secondary, aka my USB disk.

Now simply run this command, replacing “/dev/sda” with the disk label your system is running on.

sudo grub-install /dev/sda

Hopefully you’ll see this message: Installation finished. No error reported.

At this point, shut down the machine and remove your USB device.

Booting the machine should now use the new master boot record, MBR, and find the new grub scripts installed on your hard drive.

Hopefully you’ll boot straight into Ubuntu without your USB being plugged in now.

Phew!

Hope this helps you out