a fresh install of 10.04 all worked well installed apps as i wanted all went well.... system update download completed no restart required... restarted anyway only get grub prompt... repeated this operation twice.... how do i fix
getting fed up with ubuntu promising easy of use ...

What is the error message when it drops to the grub prompt?
Was it a busybox shell or a grub:sh> prompt?
Did you install grub2?
Did you add a drive or anything?
Is this your only OS? Is it installed to the HDD or in wubi or something else? Does the live disk still work?

You usually end up there if it cannot find a kernel to boot.

Please see:
http://ubuntuforums.org/showthread.php?t=1195275
http://ubuntuforums.org/showthread.php?t=1287602
https://help.ubuntu.com/community/Grub2

I got similar problems as jamesirl, so why don't I answer some of Simon's questions.

No error messages. I installed Ubuntu 10.04 AMD64 on my notebook with an Athlonx2 TK-57 processor yesterday. After the first time I installed the updates from the update manager, it dropped me to a grub shell upon restart.

Don't have experience with a busybox shell, the prompt was 'grub>', so I think it is a regular grub shell.

yes, it was grub2.

No, I didn't add a drive.

No, it was a triple boot system. In the order of installation: Windows XP, OpenSuse 11.2 for x86-64, Ubuntu. All three OSs were installed to the same HDD. Haven't tried the live disk yet since grub2 is new to me and I am still chewing on that.

I am not sure whether it is the problem of grub2 or Ubuntu's support for AMD64 yet. But they are the top 2 on my list of examination. About a year ago, when Suse's 64-bit version hit the street, I rushed to the store to buy the AMD64 machine I mentioned to just try it on. But it didn't recognize my processor as a 64-bit one and refused to install. Of course that is not a problem any more for today, but it gave me the impression that AMD64 support in Linux is still quite shaky.

It is fun for me to trouble-shoot this kind of problem, but as Ubuntu is gaining popularity rapidly, this is more annoying than funny for regular users. Ubuntu should really criticize their mechanism for releasing the software if they want to be more commercially successful.

Here is a follow-up of my last post...

The live disk actually works. When I boot from the live disk, I execute 'grub-install -v', it prints the version to be 'GNU GRUB 1.98-1ubuntu5'.
At the same time, the grub shell I got dropped in while booting without the CD prints 'GNU GRUB 1.98-1ubuntu6'. This may suggest the problem is caused by a upgrade of the GRUB.

So I reinstall Ubuntu 10.04 for AMD64 on my machine(after re-installation I got Win XP and OpenSuse back and they are working fine), fire up the Update Manager and find two grub-related packages: grub-common and grub-pc. I un-check these two and install other packages, upon restart the grub menu shows up with a new kernel installed besides the old one(the original one is 2.6.32-21, and new one being 2.6.32-23). Obviously grub doesn't do its job right because only the new kernel should show up after such an update. Both kernels work fine though.

Then I check the two grub-related packages in the Update Manager and install them. Upon restart I got dropped to the 1.98-1ubuntu6 grub shell again. So apparently these two packages are the culprits.

I am still chewing the grub2 stuff, I will come back and show how to get rid of the old kernel on the grub menu when I am done...And for now, the way to avoid all this mess is to skip the grub-common and grub-pc packages when you update your system...Hope this helps.

You may have to run the following commands from the Live CD's terminal (Applications -> Accessories -> Terminal):

List the partitions on your HDD:

Then, mount the partition that contains your Ubuntu installation (usually formatted in ext4 [if you opted to partition automatically]):

Then, reinstall GRUB to the partition:

Now, chroot into the Ubuntu partition:

Now, you can run update-grub:

See if this works.

The code
sudo update-grub --root-directory=/mnt $UBUNTU_PARTITION
doesn't work, the 'root-directory' option is not recognized.

It seems to you are trying to downgrade GRUB from version '1ubuntu6' to '1ubuntu5' by re-installing it. Isn't that going to have the same net effect as my way, where I decline to upgrade '1ubuntu5' to '1ubuntu6'?

If you choose to remove the old kernel, 2.6.32-21-generic, fire up the Synatic Package Manager and search for linux-image-2.6.32-21-generic. Click it to mark it for removal and apply the changes. After this, you have updated your system to the latest less packages grub-common and grub-pc. It looks like everything works fine for me now.