So you’ve just installed 32-bit Ubuntu 11.04 (Natty Narwhal), and in my case, upgraded from Ubuntu 10.04 (Maverick Meerkat). The upgrade process seemingly went fine and then you were asked to restart your computer. You diligently do so, only to come back to find that your computer has frozen at GRUB2 upon trying to boot the 2.6.38-8-generic-pae kernel from the GRUB list. Now what? How do you fix this?
The issue appears to stem from some form of installation issue where this new kernel isn’t set up right. Note: I don’t actually know what’s wrong and can’t investigate.
The good news is that you can use the ‘Previous Versions’ entry in the GRUB listing to boot to one of your older kernels and get your system started. Once you’re booted, then load up Synaptic Package Manager and (re-)install:
linux-image-2.6.38-8-generic-pae linux-generic-pae linux-headers-generic-pae linux-image-generic-pae linux-headers-2.6.38-8-generic-pae
You should now be able to restart your computer and use the PAE-based kernel. Thanks to a post on the Ubuntu forums for pointing me in the right direction.

Thanks!!!!!!
I had the same problem and it worked just fine!!
second Kevin. pae does not work for me either. tried 2.6.38-10, -9, -8. None worked. tried remove acpid, no help. still have to fall back to older kernel.
I just had the same problem when updating. Thank you very much !
fantastic – this solved my issue as well – even with kernel 2.6.38-9-generic-pae – i just exchanged the numbers in synaptic.
This did not fix my problem. I cannot boot except from a Live CD and then choose boot from first hard drive.
Thanks so much for this – exactly what I needed to get 11.04 working!
Magic – I posted this solution to the Ubuntu forums too, as that’s where I was searching…
[...] quick a solution for this problem: the PAE kernel was not installed properly and you just have to boot into the old kernel and reinstall the PAE kernels via apt (the generic PAE kernel allowes to address bigger RAM than 4 [...]
I was experiencing the same problem and your suggestion solved it. Thanks!
[...] no estaba dispuesto a renunciar a mis 4Gb de RAM, así que seguí buscando y encontré esta página. Allí explican que la solución es reinstalar los [...]
worked perfectly adapting it to linux-image-2.6.38-9-generic-pae
Thanks a lot! It fixed my problem!
I have tried to apply this fix several times and have not succeeded in fixing the problem. I’m not sure what the difference are between the generic-pae kernel and the plain generic kernel but I have tried both.
At the moment the only way I can boot into 11.04 is to use one of the old kernels (2.6.35).
Do you have any suggestions? Or possibly can you post the original page where you obtained the original hint?
Thanks
Not sure of which specific page (cleared my history), but essentially the page described only reinstalling it. It was on the Ubuntu forums and it was 2 posts by a single user mentioning his/her success, so the page probably wouldn’t help.
All the best in sorting out your problem.
1000 times ty. saved my day
Thanks for this post! This fixed my problem after updating to 11.04.