Debian Installation: Getting Past the Grub Error.

This post is for people who install Debian GNU/Linux and run into this error at the GRUB installation step:

  Executing 'grub-install /dev/sda' failed. 
  This is a fatal error ...

Solution: remove the USB stick from which you are installing Debian. Right now it’s /dev/sda and the target hard drive you’re trying to install to is /dev/sdb (during the installation process only). This has bitten me more than once.

Yes, seriously: the Debian installer apparently can’t figure out on its own that most likely the place you want to install the boot loader is on the huuuuuuuuge hard drive that you’ve been installing to all this time, not on the USB stick that you’ve been installing from.

I can totally understand how new research in AI would be needed to solve that problem.


  1. I this is one of the first pages I hit when I was doing a new install of Debian and got the grub rescue/error issues right off the bat. After trying several internet suggestions, on my 3rd re-install I finally figured out that I should go ahead and burn the whole live cd iso (~1.3gb debian-live-7.7.0-amd64-gnome-desktop.iso) to my usb (as opposed to the smaller iso meant for usb).

  2. Thank you very much!
    Had this error trying to install openmediavault. My USB was sda and my target drive was sdi I disconnected b-h, and when I got the error, did what you suggested, and pulled out the USB, and the installer started to use sdb.
    Apparently this error has been around for years.



  3. Glad it helped you, Steve! Yeah… if I had time I’d dig into the installer code and figure out where the bug is, but alas, one can’t stop the car for every bug one passes on the road. I hope someone who works on the Debian installer sees this post and does in twenty minutes what would probably take a non-expert a day or more to do.

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