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I just tried to do a Dual Boot with my Windows 8 desktop computer by following instructions on YouTube.

At the start, I made a 200Gb partition from my 1TB hard drive. I booted Ubuntu 15.04 by using the USB technique.

In the video at 8:30, in the box, "Device for Boot Installation", I picked the Windows 8 selection instead of the 1TB Hard drive selection. It was a successful installation.

I restarted my computer, the GRUB screen appears. When selecting Windows 8, it just keeps sending me right back to the GRUB screen.

I need help trying to get to my Windows 8! I don't really care about the files in there, just a bunch of Steam Games but all that really matters to me is to be able to use Windows 8!

I also ran Boot-Repair but somehow didn't let me. It said something about using a live-cd or Live-USB.

Melebius
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Jason
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  • First boot through the windows 8 CD or USB, repair it to run the windows properly. If it can't repair by itself(You will get the options for the repair in the windows installation CD) then reinstall windows 8 in the original partition(c drive---also backup the files in your system prior to this,you can backup files through Ubuntu live USB). Once window 8 starts working properly reinstall the ubuntu through live USB. This time use the partition according to the video. – hunch Aug 01 '15 at 08:24
  • possible duplicate of Installing Ubuntu on a Pre-Installed Windows 8 (64-bit) System (UEFI Supported) – Fabby Aug 01 '15 at 11:54

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Unfortunately, the boot loader (GRUB) installation instructions in that video are a bit confusing because the narrator keeps moving the mouse around and talking about Windows 8; but in a BIOS-mode installation (as in the video), GRUB must go on /dev/sda (the whole disk) or on an Ubuntu partition (/dev/sda6 in the video, but that might not work for reasons I won't get into). In fact, if you review the video, you'll see that after a lot of mouse wandering, the device selected was /dev/sda. Installing GRUB on the Windows partition, as you say you did, overwrites the Windows boot loader with GRUB, rendering Windows unbootable and producing the symptom you report.

The solution is a two-stage one:

  1. You must use a Windows recovery disk to restore Windows to bootability. With any luck this can be done without too much hassle, but you will need a Windows boot medium outside of the hard disk. (If you don't have one, you can download an emergency repair disk from somewhere on Microsoft's side, but I'm afraid I don't have a URL handy.) There's a slim chance that the GRUB installation will have damaged more than the Windows boot loader, in which case you'll be in for a much rougher repair. If that happens, I recommend posting to a Windows forum for help; or if you have backups of your personal files, re-install Windows from scratch and then restore your personal files. (If you can boot Ubuntu, you should be able to back up your personal files from Ubuntu. Be sure to back up to an external medium so it's not in danger of another accident!)
  2. Once you restore Windows to bootability, Ubuntu will no longer boot. You can repair this using Boot Repair from an Ubuntu emergency disk. (The Ubuntu installer in its "try before installing" mode should work fine.) Depending on how you do the repair, you may be asked about a location for GRUB. Be sure to install it to the MBR of the disk (/dev/sda, in all probability), not to any particular partition.
Rod Smith
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If you have only installed grub once, NTFS keeps a backup of the partition boot sector. And you can use testdisk to restore the backup.

Windows may not even see the NTFS partition as grub is in the partition boot sector.

https://help.ubuntu.com/community/BootSectorFix

You want to get to this screen:

http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step#NTFS_Boot_sector_recovery

If the backup partition boot sector (BS) is damaged, use testdisk to write a new NTFS BS - Rebuild BS. It will be the wrong type as XP, but then Windows repair tools will work to fix it.

oldfred
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I had a similar outcome after replacing my ubuntu 14.04 with 15.04 and ended up doing a full reinstall which I documented in response to another question:

Install Ubuntu 15.04 alongside Windows 8.1.

I think the core of my problem was the Ubuntu installer creating a hybrid partition table which windows doesn't like. I repaired this using gdisk which might save you from repeating all of the install process. But back up your data first just in case!

Community
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marcus
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