How do I fix this and install grub?

When I use gparted I see /dev/sdb has one partition and it is ext4 however when I tried to install grub I got

#grub-install /dev/sdb
/usr/sbin/grub-setup: error: hd0 appears to contain a iso9660 filesystem which isn't known to reserve space for DOS-style boot. Installing GRUB there could result in FILESYSTEM DESTRUCTION if valuable data is overwritten by grub-setup (--skip-fs-probe disables this check, use at your own risk).

I also see a mount point and 2 disk systems. One is appears to be my debian install the other appear to be a install disk. I can't seem to figure out whee on the filesytem the install disk is. There is clearly only one partition.

I installed this by using VMWare and installing to usb rather then a disk in vmware. I have another usb that doesn't suffer the problem but I used a labtop instead


Best doit "surgically" with wipefs command:

sudo wipefs  /dev/sdb

will show something like:

  DEVICE OFFSET TYPE    UUID                   LABEL
  sdb    0x8001 iso9660 2016-07-20-12-17-32-00 Lubuntu 16.04.1 LTS i386
  sdb    0x1fe  dos

So you have 2 signatures of two OS into your sdb partition.

To resolve this run the following:

sudo wipefs -o 0x8001 /dev/sdb

(It will surgically write zeros over 5 bytes of the ISO signature without touching the GPT).

After do it, run 'partprobe' or reboot system to update partition info to OS.

Source: https://bugzilla.gnome.org/show_bug.cgi?id=789898


your usb disk may indeed have some sort of iso signature on it, or at least it looks like so to grub. use fdisk -l /dev/sdb (and parted /dev/sdb print to confirm) to find where /dev/sdb1 starts. then simply clear these sectors use dd if=/dev/zero of=/dev/sdb bs=512 count=numSectorsBeforeSdb1. if you have any critical data that you cannot lose, please back it up, as always, when you do something like this.


Sorry but I can't comment other answers at the moment.

Please do NOT EVER DO what johnshen64 suggested.

dd if=/dev/zero of=/dev/sdb bs=512 count=numSectorsBeforeSdb1

This will completely DESTROY your partition table!

The first sectore (512 bytes) of disks (both HDD and USB) contains the partition table of the disk.

Overwriting that will destroy your disk partition structure.

The idea of johnshen64 is good, but you have to SKIP the 1st sector.

Therefore please use:

sudo dd if=/dev/zero of=/dev/sdb bs=512 seek=1 count=2047

The seek argument tells to ignore the first 512 bytes (partition table) and write 2047 sectors after that.


Try running grub-setup manually:

grub-setup --force --skip-fs-probe /deb/sdb

I had this issue because I accidentally wrote a CD ISO image to my disk instead of USB key. grub-setup spitted a few warnings, but in the end I was able to boot on that disk.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy