Comment 8 for bug 152261

I have the same (?) problem -- "Install Ubuntu" from 7.10 amd64 CD with preexisting /home partition appears to complete normally, but when I try to boot, GRUB says:

GRUB Loading stage1.5.

GRUB loading, please wait ...
Error 15

My environment is a little different:

/dev/hda1 -- /
/dev/hda5 -- swap
/dev/hda6 -- /tmp
/dev/hda7 -- /usr
/dev/hda8 -- /var
/dev/hda9 -- /home

The previously installed release was either 5.04 or 6.10, but it shouldn't matter in any case, because I reformatted all the partitions except swap and /home. (FWIW, I've had different show-stopping problems with the installer every time I've tried to upgrade -- 3 times so far, 3 different problems. That's why I don't upgrade at every release -- every upgrade attempt seems to result initially in several hours of frustration followed by a bug report.)