GRUB Boot Sector – Messages About Boot Sector Used by Other Software


This only happens with one of my computers. It is an elderly laptop that has had a long and varied history with several operating systems, but in its retirement it is acting as a server for my home network using Ubuntu 12.04. It is a single-boot system, there are no other systems installed.
Every so often, whenever there is a grub upgrade, I notice a message like this:

Setting up grub-common (1.99-21ubuntu3.4) ...
Installing new version of config file /etc/grub.d/00_header ...
Setting up grub2-common (1.99-21ubuntu3.4) ...
Setting up grub-pc-bin (1.99-21ubuntu3.4) ...
Setting up grub-pc (1.99-21ubuntu3.4) ...
/usr/sbin/grub-setup: warn: Sector 32 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.

Should I be worried about this? What (if anything) should I do about it?

Best Answer

It's not a big deal since there is no error reported so just warning.

But, if you wish to get rid of this, you need to wipe sector 32. To do this you have many choices:

a. Wiping the whole hard disk;

b. writing zeros to Whole sectors in your MBR and reinstall your grub;

c. Writing zeros to sector 32 in your MBR (that's what we'll do here).

To do that follow the following steps:

  1. Backup your MBR:

    sudo dd if=/dev/sda of=~/first_63_sectors bs=512 count=63
  2. zero your sector number 32:

    sudo dd if=/dev/zero of=/dev/sda bs=512 count=1 seek=32
  3. chroot and reinstall grub: Here "/media" should be whatever your chosen mount point is. Some step-by-step instructions use "/mnt" rather than "/media".

    sudo mount /dev/sda* /media/sda*
    sudo mount --bind /dev /media/sda*/dev
    sudo mount --bind /proc /media/sda*/proc
    sudo mount --bind /sys /media/sda*/sys
    sudo chroot /media/sda*

    PS: replace * by the appropriate number of your hdd

    Now update your grub:

    sudo update-grub

Note: You are not obliged to these steps, since its not an error that may affect your system.

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