Upgrading Wubi systems from 10.04 LTS is known to fail, and is not recommended at this time.
(Bug Report 653134)
If you have already upgraded and find that the system reboots, hangs or drops you at a grub prompt when selecting Ubuntu (with or without error messages), then first try to replace the c:\wubildr file from the one in c:\ubuntu\winboot\wubildr (change ‘drive’ if necessary and backup c:\wubildr first as a precaution). This fix has been confirmed by many different people, as it appears that in many cases the upgrade is corrupting the wubildr file.
Otherwise another workaround is to boot a live CD, loop mount the wubi root.disk, edit the grub.cfg (gksu gedit /mountpoint/boot/grub/grub.cfg) and remove all lines above the first “menuentry”.
If you get a read-only error on grub.cfg, then either use vi or nano, or before running gedit first run:
sudo chmod +w /mountpoint/boot/grub/grub.cfg
Note: if you install kernel updates, new kernels, remove kernels, run update-grub etc. you’ll have to reapply the workaround as grub.cfg is regenerated automatically. It’s easier to do this before you reboot (or you’ll have to use the live CD again).
PERMANENT MANUAL FIX:
I am working on completing testing for this but so far it works on 10.04.1 and 10.10 which all are affected by the same issue. http://ubuntuforums.org/showpost.php…0&postcount=78
You still need to boot the wubi before applying the permanent fix.
Last edited by bcbc; November 30th, 2010 at 05:23 AM.. Reason: added link to permanent fix