Comment 24 for bug 730225

It is confirm after 6 times of grub-install with the error "Sector 50 is already in use by FlexNet",

1. you can successfully reinstall grub only if you use - usb live cd ubuntu or other installed ubuntu partitions.
with exact the same messages as No.2
------------------------
/usr/sbin/grub-setup: warn: Sector 50 is already in use by FlexNet; avoiding it. This software may cause boot or other problems in future. Please ask its authors not to store data in the boot track.
Installation finished. No error reported.
====================

2. grub-install will destroy "grub boot menu" and you will get "grub command prompt",
 if you use the command grub-install in the following ways

you boot into "current partition", in my case sda4 contain ubuntu 11.04
(I also test with the same result in Lubuntu 11.10)

sudo mount /dev/sda(current partition) /mnt
in my case sudo mount /dev/sda4 /mnt

sudo grub-install --boot-directory=/mnt/boot /dev/sda
in my case I want to reinstall grub to sda4 so when the computer boot up it will auto boot into sda4,
which is the ubuntu partition I am using to execute the grub-install command.

It will produce this message.
---------------------------------
/usr/sbin/grub-setup: warn: Sector 50 is already in use by FlexNet; avoiding it. This software may cause boot or other problems in future. Please ask its authors not to store data in the boot track.
Installation finished. No error reported.
====================
you will get grub>
and not your grub menu any longer.

I don't know "if I should post this as new bug or not".
========================================

But certainly it is not correct when grub report "No error reported".
And you will get a "destroyed grub menu" after reboot.

note== the reasons
 I start to do grub-install from Lubuntu 11.10 to force grub to start Lubuntu 11.10 as default os.
because the "startup-manager" fail to change grub menu as it did for previous version.
which I don't know why, bugs or just incompatible grub version in sda.
But the above "bugs" I have tested and found to be on both Ubuntu 10.04 and Lubuntu 11.10